An *excellent* article on the when, why, and how of doing battery pulls on your BlackBerry. It's recommended many times on these boards to fix a multitude of problems because it WORKS! Here's why:
http://crackberry.com/blackberry-101-battery-pulls-when-why-and-how
And if you don't want to click the link, here are a few of the highlights:
Maybe [your BlackBerry] is not working as fast as before, the internet is stalled, or application memory is gone and nothing has been added. Is it possessed? Do you want to hurl it against the wall?
Before exchanging the device or panicking that it’s broken, know this. It’s normal; from time to time, your device might become slow and unresponsive. There is a quick and simple way to troubleshoot these issues. In these cases, it’s necessary to reset your BlackBerry device by performing a hard or soft reset. A hard reset is also called a battery pull.
Essentially, a battery pull restarts the operating system on your BlackBerry device and is just like rebooting your PC when it’s experiencing problems. It is not the same as using the Pwr Off/On button. This only places the phone in standby mode. Not only does a battery pull solve various problems with your device, it also frees up application memory and shuts down applications running in the background that can drain battery and resources.
A battery pull can help when:
Hardware Problems
- Device display freezes or jerks
- Torch/Storm devices lag when going from Portrait to Landscape and vice versa
- Keypad/Trackball stops responding or does not work
- SIM card errors
Software Problems
- Java code or module errors appear on screen (e.g. Uncaught exception)
- Applications are slow, unresponsive, do not load or lag
- Theme issues
- Bluetooth errors – connecting, pairing, etc.
- Installing/Uninstalling Applications & Theme)
- Music streaming apps (Slacker, Pandora) experience continuous buffering
- Social networking apps (Twitter/Facebook) indicate there is no connection available
- Memory leak – available application memory drops
- LED Notification - LED keeps flashing when there are no new e-mails, texts, alarms, etc.
Maybe you don't WANT to physically remove the battery; I know I don't like removing the protective case repeatedly to take the battery out of the phone. Thankfully, there are third party "apps" that simulate a battery pull that you can download from BB App World. I use QuickPull by Steelhorn Software (free); it will reboot your device on a schedule you set, or you can do it manually as needed. A+ Reset ($2.99 after free trial), deReset ($5.99), Restart Me (free) are other options, all available through BB App World.
HTH someone...your BlackBerry can do a lot for you, but you do need to do some caretaking and maintenance. 
Hi SuzyQ,
I appreciate you sharing your tricks of the trade and words of wisdom to our community members. Your information in this post definitely explains the "why" behind some of our basic troubleshooting steps. Your feedback in greatly appreciated.
Thanks for being an active member in our community forums,