SHOWS FOR YOUNGSTERS AND THEIR PARENTS TOO : ‘Ghostwriter’ solves the crimes on KCOP; Nick’s kids get a ‘Big Help-a-Thon’; TLC’s weighty ‘Small Talk’

Using mystery and adventure to show kids that reading and writing can be fun and rewarding, Ghostwriter makes its debut on commercial television (KCOP, Sunday at 11:30 a.m.). The series, previously seen on PBS, focuses on six multicultural teens and preteens working as a team to solve neighborhood mysteries. A ghost communicates with the team through computers, chalkboards, notebooks and other written means. The mysteries unfold over four half-hour episodes. For ages 7 to 12.

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Tim Allen, Shaquille O’Neal, LL Cool J and Cooli are expected to be among the celebrities joining Nickelodeon’s Third Annual Big-Help-a-Thon (Nickeloden, Sunday at 9 a.m.). The event encourages kids to volunteer to help out in their communities. The eight-hour event at Pacific Park on Santa Monica Pier features special programming, live entertainment and segments from other parts of the country that focus on volunteering. For ages 5 to 18.

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In The Prisoner of Zenda, Inc. (Showtime, Sunday at 8 p.m.), a 14-year-old computer genius, Rudy Gatewick (Jonathan Jackson), becomes CEO of a major corporation and is kidnapped by his ruthless Uncle Michael (William Shatner). Another 14-year-old look-alike, who knows nothing about computers, is recruited to fill in for the missing Rudy. The new recruit (also played by Jonathan Jackson) must figure out how to play in a championship baseball game and attend an important stockholder’s meeting at the same time. For ages 10 to 17.

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Bruno the Kid, the world’s youngest secret agent, continues his dangerous missions (KCAL, 8:30 a.m. weekdays) in this animated series. Bruno (the voice of Bruce Willis), an 11-year-old computer whiz, works for a secret organization to help maintain world peace. For ages 6 to 12.

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Small Talk (The Learning Channel, 4 p.m. weekdays) features seven kids between ages 7 and 9 who answer questions and give their opinions on major and not-so-major issues. Contestants win points by guessing what the kids will say. For ages 7 to 10.