Follow these instructions and you'll be fine:
How-To Root your stock 2.1 Droid
Make sure you have the latest version of RSD Lite, as well as the latest Motorola USB drivers. They install super easy. You don't really need to know anything to install those programs.
A couple of other tips:
* Once you install RSD lite, set it to run as administrator. Ask if you don't know how to do that. The easiest way is to find the program on your PC (the one that the desktop shortcut points to), right click on it and set it to run as adminstrator. Ask if you need help.
* You will be installing an "SBF" file. This is just a file that you will be transferring to the phone using the RSD Lite program. Download the SBF file and put it directly on your C: drive, not in a folder. Don't ask why, just do it.
* Make sure your phone is charged up. You don't want to deal with a dead battery while this stuff is happening.
Other than that, this is pretty simple. Much easier than you might think. Once you've rooted it, download ROM Manager from the market and use it to install custom ROMs, like CyanogenMod.
Ask if you need help. If you haven't noticed yet, there is a sub-forum here that is devoted to this sort of thing. I'm very new to it. I just rooted my Droid a couple of days ago (on an old one that is going back to Verizon) and again today on my new, working phone. Ask if you need help!