Okay... so WHY do I want to Unlock my Extended Memory...!?
 

Like most of us, I've done my share of reloading various formations of the Kitchens over the past year, and have gotten pretty good at rebooting the Verizon XV6700 unit with the latest ROM. And - like many of my fellow PPCGeeks, I've opted to install some of the programs on the Storage card, rather than on the unit.

My question is this... since we have already uploaded all programs desired, do we need to keep the program files found on the Extended Memory... or, can I simply delete them and use that space for email buffering, etc. - ?!?

Another thing... I've deleted the files in the past - without selecting to "Unlock" from the Program directory. What exactly does that "unlock" feature really do in the first place...??!

Just curious.

You could check this out.
http://forum.ppcgeeks.com/showthread.php?t=1258

It doesnt really address your last question but it will tell you what you need. Though they say to save certain things on the ext memory but Ive deleted all of mine and have no problem. I dont use my data connection just wi-fi and some of the cabs on there deal with the data connections. Its all in there including what each one does and how to add the stuff you want in there so that it will load on a hard reset automatically.

I've copied every extended rom I ever had onto the storage card (which is itself backed up on my system), then I just use the ER for more storage. Typically I fill it up with installed programs. This is logically similar (from the OS's point of view) to installing programs on the storage card, but it's physically similar to installing in main memory, so there are no worries about it becoming unmounted or waking up too slowly.
If by "email buffering" you mean saving attachments, the 9.9MB available can fill up pretty quickly if you are the type to save attachments on your phone. This gives rise to the No. 1 complaint about unlocking the Extended Rom - poutlook can't see the real storage card, so you must save attachments to main memory or (if save to storage card is selected) to the Extended Rom.
Not sure about the details of the unhide/unlock processes, but the ER needs to be unlocked to be able to install programs there and have them survive a soft reset. Once programs are installed, supposedly you can re-hide the ER using the registry tweak, and the programs will still work. I keep mine unlocked and unhidden.