Yeah, X-Men: Evolution got the axe from Marvel.
STUPID, STUPID MARVEL!
I second “Bone”, BTW.
I like them a lot, but I wouldn’t try out the Star Wars titles on a six-year old, especially not the Republic series. They’re hip deep in the Clone Wars right now and the bodies are piling up. Good stuff, but not kid-friendly.
Also, if you’re going to go into an actual comic shop, I’d suggest “David and Goliath” from Image, about a kid and his flying pet lion. It has a very ‘Iron Giant’ feel to it. Also, their new title “Invincible” seems to be just a lot of fun in general and is 100% super-hero material (save for the occasional exploding teen).
And while I agree that modern X-Men probably isn’t suitable for a young kid (aside from certain titles being basically crap, I mean), you might want to consider picking up Essential X-Men vol. 1 from your Borders or B&N: it’s Giant-Sized X-Men and about ten of the comics following in B&W for $13. Also, Marvel’s new New Mutants title would probably be a good choice for a young reader. Give issues 1 & 2 a shot, very fun vibe there.
If you don’t mind exposing your kid to 80’s nostolgia, there’s always the new Thundercats TBP – but only the first one. The series that come after it are really rather dark. The “Thundercats: Hammerhand’s Revenge” that just started coming out looks to be about cartoon-level, but it’s too soon to be sure.
Hope this helps and happy reading!