I had some issues with the ADB commands for preparing my rooted Nook Color for on-device app install (primarily due to microcrap's 64-bit Vista) so I found a very easy method.

In the Market, there's an app called "Sqlite Editor" from the folks who make "Root Explorer" - it's about $3.07 US$ but I bought it anyway.

With this [AFTER A BACKUP!] I was able to directly edit the settings.db (sub category SECURE) and change the following:

'install_non_market_apps' from the default value of 0 to 1 and following a SAVE and REBOOT I can now install directly from my SD Card.

While I was doing this, I find a large number of additional entries including (are you ready for this???) bluetooth_on!

Dare I do this???

I also posted this in XDA-Developers excellent Nook Color Forum and I was thinking that may we should acknowledge the very excellent work that they do there on behalf of our beloved Nooks!