Mistakenly, I found that iPhone 2.0 has a built-in screen shot feature: 1. Hold the "home" button 2. Press on "power" button 3. Release "home" or "power" button, you'll see a short white flash 4. Go to "Camera Roll" and find you screen-shot
If you're using iPhone FW 2.0.x you probably noticed that on (almost) each sync between your iPhone and iTunes a backup operation is performed, and it may take long time (for 100 apps, it may take more than 3 hours) and this is annoying feature for people who sync their iPhone frequently.
This application by Dennis Nederlof is very useful and does the trick: http://www.microseconds.com/backupswitch.html