Go with it! There's no stopping a kid like that from reading. Even though my son knew the alphabet and all the letter sounds before age two, I still assumed he'd learn how to read in school. Then at age two, he started picking words out of the newspaper at breakfast. When I told my husband DS was reading, he refused to believe it (thought it was memorization) until DS started reading obscure signs at gas stations and in grocery stores. It was bewildering, exhilarating and a little bit frightening. But it's all good!
I agree with the advice above. Go to the library at least once a week, check out as many books as you're allowed, and read until your son is bored with it. Play lots of word games involving rhymes, puns, homonyms and what not. Check out Starfall when he's ready to use the computer. You're in for a wild ride!
