As you may know, iOS5 currently has a tethered jailbreak. This means that after you have jailbroken and installed most stuff you care about, you go to reboot your device, and it will no longer boot. You will be either stuck at apple logo forever, or you will get to itunes restore screen. When this happens, you have to hook up to your computer and use redsn0w "just boot" feature which gets you rebooted successfully again.
To get us through this period, I have worked on a semi-tethered solution. The semi-tethered jailbreak will allow you to reboot on the road, but with limited functionality. It is enough that you are no longer stranded, and you can use your phone, text, and many other features. This is just until you get home and can use redsn0w again to "just boot tethered". Once you do that, you're back to fully functional state.
1) Can use phone, sms (text messages)
2) Can use every other stock app on iphone.
3) Cannot use mobile safari
4) Can use other appstore web browsers such as atomic web browser
5) Cannot use mail app. You could install a gmail app from appstore or such instead.
6) You cannot use any jailbreak tweak, app, cydia until you boot tethered.
7) While in the semitether booted state, you should not add a jailbreak ios5 notification such as sbsettings to notifications during this state or your device will be stuck in a respring loop until you get home to "boot tethered".