I'm having trouble setting up the Android SDK. I've set up Eclipse before but it didn't work, so I uninstalled it, but I'm trying again.
Does Eclipse need to be extracted to a particular folder for it to work? Where should I extract to?
Edit:
I'm using Eclipse 3.5 on Win7 Ultimate x64
No, Eclipse can be extracted anywhere. Make sure you follow the steps detailed in the guide "Installing the SDK".
Eclipse should be one of the most straightforward installs you have ever done. Make sure you have a Java SDK installed prior to extracting Eclipse. Otherwise it should work out of the box. Be sure not to move the eclipse executable out of the directory that you extract it to (make a shortcut to move instead).
The Android SDK should also be largely painless. Use the tool provided with the SDK download to setup the versions you want. The documentation is pretty good for this. (see Brian's link)
It can be much trickier to get the drivers for specific handsets working though, so you have that to look forward to down the road. They will come from the individual manufacturers developer websites.
Also is this for Win, Linux, or Mac? I will link you a walk through for the one you need.
Video tutorial for installing Android SDK on Win7 - http://www.youtube.com/watch?v=YeWH6Bj1DYw&feature=related
Installing Eclipse on Win 7 64bit - http://goo.gl/eNT6 and http://goo.gl/1Gvw
Ignore the last link to the JRE provided in Andrew's answer, you need the Sun JDK (5 or 6) instead of just the JRE (The Java Development Kit can contain multiple Java Runtime Environments). The official documentation Android provides makes this distinction quite clear. You need the JDK. --> http://developer.android.com/sdk/installing.html#Preparing
Also, the ADT plugin for eclipse sometimes doesn't update correctly. In that case, try to manually remove the 's' from the 'https://' and if that doesn't work, click on one of the tabs of the dialog and look for the checkbox which forces the use of secure mode, and then of course, make sure there is an 's' in the 'https://'.
Also make sure you've updated your system environment variable called 'path' to make sure the tools inside the tools/ folder from your android sdk folder are accessible from anywhere your command line/Eclipse might decide to call them from.