I'm only one month into my iOS development, and already have a sweet gps app running perfect on the iPhone simulator. I'm about to pay the 99 USD to be able to try out the app on my real device (iPhone 4). My question is: can I unplug the device after downloading the app. What I mean is, can I test my app unplugged from my computer without the whole process of submitting it to app-store etc.
If I can't, then I have to run around town with my laptop + iPhone for testing. That's pretty dumb.
This is not an issue.
You can provision a certain number of phones to work with your developer license, and install and run your app on it. It will look just like any other app.
Good luck!
If you install and run with your team provisioning profile you can also run the app from your iphone without a certificate. :)
The short answer is, "Yes, You can".
What everyone said about provisioning, and multiple devices and everything was correct.
From a simplistic point of view - when you run your app in the debugger (connected to the iPhone) - it actually installs it on your iPhone. So when/if you disconnect the phone from the debugger - it's still on your iPhone - and can be run just as any normal app.
(With respect to your other question)
You can provision certificates for up to 100 devices. So if your friend has a device, you can get his "UDID" (avaialble via iTunes). You can email him a provisioning profile (you generate) for his device and a copy of your app (provisioned under that profile). He drags-and-drops both into iTunes - syncs, and he has the app running on his machine.
Note that these types of certificates only last for 3 months - so you'll need to generate a new one for him - or give him a "real" copy from the AppStore after release.