With our pediatrician's guidance (and, please get the blessing from yours before starting) we started our baby on solids at 4 months. Also, our baby turned into a 'happy spitter' once he began to roll over and scoot.
To deal with the spitting up, our ped. had us switch to Enfamil AR (has rice starch added to the formula) so that the formula is 'heavier' and less likely to come up. It took about 2 1/2 weeks but we are noticing a huge difference.
About the food - don't worry yet about your baby's attitude to food, except that when you do feed your baby solid act as if it is the yummiest food you've ever tasted on the planet. Babies like to please and imitate, and right now eating is more about learning how to eat and trying the different textures (taste buds are not as fully developed yet) and temperatures.
Here's the schedule our ped gave us for starting solids. Again, although this is a good guideline, EVERY child is different and unique, so consult your ped.
Week 1 - rice cereal with breakfast (1st day runny, slowly thicken it, increase to 1-2 tablespoons as baby is comfortable)
Week 2 - rice cereal with breakfast and dinner, yellow veggies (squash, sweet potatoes, carrots...3 days in a row for each) with lunch
Week 3 - rice cereal with breakfast and dinner, green veggies (T,R,S...peas then green beans, again 3 days in a row) and yellow veggies (same as week 2 but M, W, F) with lunch
Week 4 - same format as week 3, add fruits as 'snacks' if needed
Some babies are ready this early and some are not. Many people stick by a hard and fast '6 month' guideline, but since my pediatrician is an FAAP (fellow, American Academy of Pediatrics) I trust her 100%. If she has not lost the tongue-thrust reflex (she pushes the food right out of her mouth when you give it to her) or if she is unable to hold her head up/sit up supported, then she isn't ready.
Follow her lead and take it easy. Expect messes! And, most of the baby food you buy is straight up veggies and water or fruit and water, so don't worry yourself just yet.