My 5 month old is a wonderful eater - however the pediatrician warned us against putting the rice cereal in the bottle (something about breathing in the cereal since they breath as they drink??? i'm sure that isn't 100% verbatim). We tried it before the ped told us not to, and it just clogged the nipple anyways. What we do is prepare a bottle for bedtime, pour a small amt of cereal into a bowl and add formula. To start out, make the consistency very thin - and watch, because it thickens very quickly. Getting him to open his mouth fully will make it easier to get the spoon in. Then, slowly add some fruit to the cereal at bedtime, and at breakfast. Then add some veggies and and some fruit for lunches once he gets the hang of it.
We started with apples and peaches, and now use various Stage 2 foods, he likes anything. The veggies he likes best are sweet potatoes and carrots, and slowly he is adapting to green veggies. :-)
(My 5 month old has been on cereal since 5 weeks, and has been eating breakfast, lunch and bedtime food since he was 3 months (i'll take some flack for posting that, but all children are different and he's had no problems. Our twins started at 3 months as well). We actually gave him a few bites of homemade mashed potatoes last week and he loved them, which makes me want to start making his food instead of buying it. We'll see!).
Good luck, experiencing this with your little guy will be fun for all of you!