Have you tried rebooting the phone. The 2.0.1 update as far as I can tell has fixed many of the lags and crashes found in 2.0
A reset/reboot is:
Go to Home Screen
Press and Hold Home Button
Keep holding and press and hold Lock Button
Keep holding Both
You will see Slide to Turn Off (Don't let go to slide, just keep holding)
The phone will turn off (in time, but screen will look like it has some white lines)
Keep Holding
When you see the Apple Logo, you can let go.
Turning off via the Slide to Turn off while good and fine to turn off, is more like the Sleep Mode on a computer. Thus any locked up issues in memory remain when you turn back on. A reboot as described is like doing a real Turn off and Turn On on a computer.
You may also wish to read this tread about reboots and odd application behavior.
http://discussions.apple.com/message.jspa?messageID=5851978#5851978