Personally, I watched my son for developmental signs of readiness, rather than relying on a particular age range. He started eating puffs at 7-8 months, when he demonstrated that he could pick up small items with his thumb and forefinger. That pincer grasp is one of the key signs of readiness, and I found that he could use it reliably around that age. He LOVED eating puffs, and for a while that's all I would give him to practice eating finger foods because he didn't have any teeth. He now has one tooth, which he's had for the past two weeks, and it doesn't seem to make a difference so I've been branching out from puffs into other things. He had his first Cheerios last weekend, and LOVES them. And frankly, I'd rather give him Cheerios than puffs because they actually have some nutritional value. Puffs dissolve faster, and were a great starting point, but they're practically 100% sugar and not much else.
Anyway, my son is now 10 months old, and he has decided he's done with being fed. So we're starting to make his meals more finger-food oriented. Lots of bite-size veggies and fruits (Beech Nut makes a good variety of "Table Time" bite sized fruits and vegetables with less sugar and preservatives than the Gerber versions), shredded cheese, shredded chicken, and LOTS of Cheerios. He's happier at mealtimes now, and frankly, so are we. :-)
Have fun introducing your baby to new finger foods--it's amazing to watch their reactions when everything is so new and exciting!