If you're one of those parents who likes to keep your kids' viewing options simple - PBS, Nickelodeon, videos or turn it off! - this article may not be for you. But if you're like most parents, less restrictive but with a watchful eye on your children's choices, here's some help in navigating the new shows for the under-12 set this fall. Preschoolers On shows aimed at 2- to 5-year-olds, somebody always seems to be singing a song. And no one has more reason to sing than the folks at Nickelodeon, the overwhelming choice of the youngest viewers thanks in large part to perennial hit "Rugrats" (7:30 a.m. and 6:30 p.m. weekdays). Now the "Nick Jr." lineup, airing 8 a.m. to 1 p.m. weekdays, has grown another perennial: "Blue's Clues" (8:30 and 11:30 a.m. weekdays). Host Steven Burns enlists his audience to help him solve various puzzles created by a whimsical animated blue dog. Among the new episodes this third season: a pre-Thanksgiving lesson on being grateful. Over on PBS, the weekday "Ready to Learn" block doesn't have new shows, but it does have new episodes of "Arthur," "Puzzle Place" and the pre-preschool crowd's favorite, "Teletubbies." "Noddy," a charming update of "The Olde Curiosity Shoppe," has begun airing Sundays at 9 a.m. on Channel 19. Noddy is a humble wooden toy who expands his world whenever he uses his imagination - and teaches kids to do the same. The Disney Channel just launched a new "Little Kids" block from 7:30 a.m. to 1:30 p.m. weekdays and 5 to 9 a.m. on weekends. "Out of the Box" (9:30 a.m.) features a daily clubhouse singalong with two adults and seven kids. "Bear in the Big Blue House" (7 a.m. and noon) stars a lovable 7-foot creation from Jim Henson's shop. The rest of the Disney morning lineup has classic Disney cartoons and animal shows. "Jay Jay the Jet Plane" is the newest addition to The Learning Channel's "Ready, Set, Learn" block of educational shows (5 to 11 a.m. weekdays). "Jay Jay," debuting Monday and airing at 6:30 and 9:30 a.m. weekdays, is based on the home-video series about a curious little plane, his six flying friends and the real-life humans who keep their engines in tip-top shape. Fox Family Channel, which launched in August, has a new Captain Kangaroo at the helm of "Captain Kangaroo's Treasure House," a two-hour block of shows for preschoolers airing 10 a.m. to noon weekdays. Among the regular features are repeats of the long-running PBS series "Shining Time Station" (with George Carlin as the conductor) and "Thomas the Tank Engine. " The half-hour "Magic Adventures of Mumfie," about a curious little elephant, is from "Thomas" creator Britt Allcroft. Among local stations, KCWB, Channel 29, now airs PBS defector "The Magic School Bus," 7 a.m. weekdays; "Bloopy's Buddies," which encourages exercise and good nutrition - and throws in Jonathan Winters for good measure - at 2 p.m. weekdays; and "The Mr. Potato Head Show" (8 a.m. Saturdays), with new adventures of the exuberant tuber. On Saturdays, KMBC, Channel 9, offers an hour of high-quality all-ages cartoons sandwiched between several hours of animated slapstick you may not want the under-6 crowd watching. "101 Dalmatians: The Series" (10:30 a.m.) actually has an educational message and "The New Adventures of Winnie the Pooh" (11 a.m.) has won an armload of awards from parents' and teachers' groups. On Sundays, KCTV, Channel 5, offers "Franklin" at 7 a.m. Paulette Bourgeois' stories are about a young turtle who often gets in over his shell while learning life lessons. Older kids Fox Family's "Morning Scramble" block (6 to 8 a.m.) features the high-energy Freak and DJ Germ introducing such classic kidfare as "Pee-wee's Playhouse" (6 a.m.) and "All Dogs Go to Heaven" (7:30 a.m.) "Toon-A-Casserole" pretty much describes the noon-to-2 block, a hash of warmed-up cartoons from "Dennis the Menace" to "The Real Ghostbusters. " And "The Basement" (2 to 5 p.m.) is loaded with kidcoms introduced by three improv comics. Disney's megamovie "Hercules" is the basis of a new madcap Saturday-morning cartoon at 7 a.m. on Channel 9, leading into the popular "ABC Saturday Morning. " "Squigglevision" (11:30 a.m.) is the new name for "Science Court," last year's tongue-in-cheek educational cartoon from the animator of "Dr. Katz, Professional Therapist. " That's followed by the second season of one of my favorite educational shows, "Popular Mechanics for Kids." CBS (Channel 5) overhauled its entire Saturday-morning lineup after last year's shows bombed in the ratings. All of the new offerings come from the Canadian animation shop Nelvana; most are based on best-selling children's books. "Anatole," based on the popular French comic about a family of mice, airs 7:30 a.m. Sundays. Channel 29 introduces two new shows capitalizing on the popularity of medieval adventure series. "Mystic Knights of Tir Na Nog" (4 p.m. weekdays) follows the adventures of a young medieval Celtic hero, while "Young Hercules" (no relation to the new "Hercules" cartoon) is an action-adventure featuring the mythical hero as a teen-ager with a distant dad who happens to be Zeus. Channel 62 adds "BRATS of the Lost Nebula," the most unusual new kids show this fall, 9 a.m. Sundays. A product of the Jim Henson shop, it combines muppetry and computer effects in a sci-fi adventure about kids marooned in space. "Histeria! " yet another frantic cartoon from the Warner Bros. shop, joins 62's after-school lineup at 3:30 p.m. On Saturdays, Leo the MGM Lion and his family are the basis of a new cartoon, "The Lionhearts," at 8 a.m., followed by a computer-animated action-fantasy, "War Planets." The Discovery channel is adding a game show to its Sunday-morning kids block (8-11 a.m.). "Zap It! " (8:30 a.m.) uses a standard quiz format with Discovery channel-skewed questions. NBC is sticking to its strategy of teen sitcoms and basketball-related fare on weekends. The quasi-educational shows air from 9 a.m. to noon on Channel 41.

