My ds is 6 and we're getting ready to start homeschooling in the fall (he's in public school k-garten right now
We are reading about the Trojan War currently and doing a little study on the weapons and armor of the Greeks. From there, we'll probably do a bit more exploration into classical mythology and see where that leads us.
When he's about 8-ish, I think, we'll start with Minimus and move on from there. I'm thinking I will just use a variety of things I've collected over the years -- including Lingua Latina and Cambridge -- and do some spoken Latin with him too -- in fact, I hope to start the spoken Latin next year. I found that the students who do better and really enjoy Latin are those who develop a reading competency really early, and LL does that remarkably well -- and spoken Latin really opens up the students' minds to the language. Even if you cannot speak the language, I would read it aloud as often as possible. Any of the reading-based texts should help, though, like Ecce Romani (though I don't personally care for that text).
ETA: I think level one when he's about 10-11 is fine, but we may wait. It all depends on how open he is to the idea.
Once the child has a good handle on grammar (in my program, that usually happens about the end of level 2, but there's no need to rush, and in fact my best students are those who spend 2 years on level 1) you can just pick and choose from a variety of Roman authors (my favorite site to get these is www.thelatinlibrary.com
-- and the site also has nice links to online Latin grammars and sheets with paradigms). Catullus and Martial are quite fun (but can be very *ahem* raunchy, so choose carefully), Caesar can be interesting (as long as that's not the only thing one does), but lesser-known texts can also be scream to read -- I love Lactantius, and some of the Germanic law codes, for example.
Here are some other places you can explore:
-- a tremendous resource; join the discussion list for lots of cool ideas from Latin teachers all over the world
-- virtual Rome
Excellence Through Classics -- the American Classical League site for elementary, middle levels of Latin
From these places (and these are just a few) you can follow links all over to other really great resources.