I no longer have my iPhone, but I wanted to know if there was anyway I could access the pictures that I uploaded to Photostream before I got rid of the phone. Or are they all completely lost?
If you have a Windows PC, you can download iCloud Control Panel from Apple. Once installed, open iCloud Control Panel and enter the same Apple ID and password as you used on your iPhone. Any photos taken within the last 30 days (or up to 1000, whichever limit was hit first) will be downloaded.
If you're on Mac, have OS X v10.7.3 or later, and have iPhoto '11 (v9.2 or later), go to System Preferences > iCloud and again, sign in with the same Apple ID and password as your iPhone. Open iPhoto, click on Photo Stream in the left column, and click Turn On Photo Stream when prompted.