I found the information below posted on the VZW support forums and tried it on my D2 and it works great.
10 Steps to Play Farmville on Facebook with Android 2.2 update
Farmville is very popular and now with 2.2 release everyone can play right on their phone. If you tried to play after updating to 2.2 Froyo you probably received an error that says it isnt available on this device.....NOT SO!!
But you do need to make a change in your browser settings:
Instructions are for the default web browser.
1.Download and install Flash from market
2.Open your browser, go to facebook.
3.type into the browser about:debug and press go. The browser will go right back to the same screen you were on previously and it appears that nothing happens.
4.Press your menu button(bottom left physical button)
6.Scroll down to "Settings"
7.Scroll all the way down to the bottom where you see "UA STRING"
8Choose "Desktop" This will "trick" websites into thinking you are logging in from a PC computer and not a Droid.
9.Hit back until you are on the facebook page again.
10. Refresh your browser and launch Farmville!!! Enjoy it.