K.L.
I know where you are coming from. I wanted to wait as long as possible to put my girl on solids. She has shown all the signs of being ready but I still resisted until she started waking up more frequently at night. My M. said that's the sign. So today I actually gave her her first tasting of brown rice cereal.
If he "loves to eat" it's probably bc he is ready for solids and needs more than the formula/breastmilk is giving him anymore.
The signs of being ready are: has doubled birth weight, its AT LEAST 4 mo old, can hold head up w/ no problems, can sit up with assistance and is eyeing your plate. Also, they say 6 mo bc of a special reflex babies have until around that time that makes them push things out of their mouths with their tongue to prevent choking. The first few times you feed your little guy he might do this but he'll catch on after a while and manage to get some of it into his tummy!
I am hoping to keep her on rice and breast milk ONLY for as LONG as possible to prevent allergies to foods from early exposure and just to keep MY life simpler!
I do know babies who are 5 mo, though and already on cereal and pureed veggies. I would NOT do the cereal in the bottle, they say it's a choking hazard. Just make it really thin (slightly thicker than milk) to start and spoon feed it to him.
Also, try to make sure his first non-cereal food is a veggie so he doesn't develop a major taste for sweets but instead enjoys a variety of foods. Have fun and enjoy those first MESSY feedings--and don't forget the bib! :D