Last night when I was out, I tried going to Cydia. It loaded for a few seconds, then springboard crashed. I rebooted, and it happened again. The same thing happened when I tried going to the App Store. Later that night, Mail and Safari had a similar issue. After several crashes, my iPhone (4) hung at the Apple logo for a while, so I did a hard reset. When it turned on, those apps were fine. No crashes whatsoever. More recently, random third party apps (RunPee and DoodleBuddy) are crashing the springboard. The only thing I installed recently before this issue was an update to NoAccessorySplash iOS4 1.2-2. I just uninstalled it, and as far as I've seen, no apps have crashed the springboard yet. Just figured I'd post this in case anybody else has a similar issue.