The hardest thing about doing this was trying to decipher the jargon used by the developer's community. The instructions were very vague- they would tell you to do something, assuming that you already knew how to accomplish that task. "You flash the new ZIP file, dummy- don't you know anything?" So do you clear the cache first or just flash the ZIP file? Is there another step you do before unmounting the SD card?
The first few days after getting my Nook I could not find clear instructions on how to install Android- all of the links kept going around in circles. Finally I ran across a few videos on YouTube that demonstrated a few different ways to upgrade your Nook. There were quite a few different choices- some people just installed Android Marketplace on top of the B&N OS to allow them to run more apps while other people actually replaced the OS. And to replace the OS you had a choice of doing that to the internal memory (thus voiding your warranty) or by running the OS on an SD card (which is very slow). And there were several versions of Android being used: 2.2 (Froyo) 2.3 (Gingerbread) and 3.0 (Honeycomb).
It was Honeycomb that attracted me like a fly to, er, honey. Besides the very pricey Motorola Xoom, none of the Android tablets were running version 3.0, the first version designed for a tablet and not a phone. Well, Google has not yet released the full SDK for Honeycomb to the public yet, there is only what is called a "preview". I ran that OS first off an SD card just to get some idea what 3.0 would be like, but it was a trial OS, not something fully functional.
So once I learned how to backup the original B&N OS I started flashing in different versions that different people recommended finally settling on CyanogenMod or CM7 with Dalingrin overclocking (to increase the CPU speed from 800mHz to 1100mHz). They issued a new patch every night (called the nightlies) with new capabilities and new bugs, but they finally came out with a stable release on the April 11th. Woohoo! That one is working really well.
EDIT Dalingrin will be releasing a new kernel which will increase the CPU speed to 1300mHz. And someone else came out with an app which allows you resize the cache used with the SD card. Increasing the cache from the stock setting of 128kb to 2048kb increases the read speed by 80%. If we were to wait for the vendor (B&N) to implement improvements like these I think we would wait forever.