I don't now of any sites right off the top of my head, but you could easily do a search and find some.
As to a good, inexpensive (as opposed to cheap) pellet rifle, look no further than a Benjamin 397 or 392. Both are basically the same rifle, except for caliber; the 397 shoots .177 pellets, while the 392 shoots .22. Check around your local area and see what caliber of pellets are stocked in greater quantity, and let that be your guide as to which gun to choose. I have the 397 (both guns should run about $120.00 to $150.00, depending on area), and have used it to take a lot of small game. It is very powerfull (800fps with an 8 grain pellet), as well as extremely accurate. It WILL kill rabbits, but you need a realy good head shot. I have been using pointed pellets, but I'm ging to be trying some HP pellets, if they ever get here. With the right pellet, and a good shot, you can easily take quail and small squirells. Rabbits and the like will take GOOD pellets and excellent marksmanship, but are well within reason. Y9ou might also consider the Sheridan Blue Streak, but it's something of an oddball in .20, and you might have trouble finding pellets locally. It also costs about $25.00 more than the 397. There are more powerful pelet rifles out there, but you're going to be paying $75.00 to $100.00 more to get an extra 200fps. Also, I would stay away from the spring-piston guns, as I prefer pneumatics, because you can adjust the power with a pneumatic; with a springer, one pump gets you max power, and nothing else. Versatility is greater with a pneumatic.