Step 2. You must activate the microcell on your at&t account.
Step 3. You then add your at&t wireless numbers (every single one in your household) to your microcell. (don't forget the at&t cellular capable tablets, and don't forget your work phone if you have one that uses at&t)
Step 4. Port your number to straight talk - give yourself about a day for this to be finished.
Once your number is ported over to straight talk, your phone will continue to talk to at&t's network through the microcell. I spoke to at&t about this and they do not allow you to manage a microcell if you don't have an at&t account. If you switch over all your phones to straight talk (As I did) you will lose the ability to manage your microcell. As long as your number does not change and you don't switch carriers your home should continue to provide you with 5 bars of cellular coverage thanks to the microcell.
This same procedure may work for other MVNO carriers that use GSM 850/1900 through at&t.
Confirmed by one of my readers:
Here are some possibilities, gathered from wikipedia. If anyone has tried any of these, leave a comment.