I think it's awesome that you would do this!
I don't know the process for donating your blasts, but I do know that when we signed all of our paperwork before doing our cycle, there were places to specify what we wanted to do w/ any leftover embryos.
First and foremost, please PLEASE make sure that whatever group you use, they do not charge large amounts of $$ to the receiving couple.
In my research I found that 90% of the programs out there charged almost as much to the couple as doing donor egg.
I don't have any good answers for your questions here - but I just wanted to let you know what a wonderful thing you are thinking of doing. I know so many people who have benefited from the kindness & unbelievable generosity of strangers through embryo, egg or sperm donation. We are so incredibly grateful to our sperm donor for giving us the chance to have a child. Though he was an anonymous donor - I think of him fondly and with gratitude all the time.
Thank you for your generous spirit - hopefully you will find a good way to donate and provide a miracle to someone!
Me (34) DH (32) TTC #1 since 2007
TTC naturally/ timed BD 2007-2009 July 2009 SA #1 zero count
July 2009-March 2010 more tests for DH
June 9 & 10, 2010- First & Second IUIs with Donor Sperm (Clomid, Estrogen, HCG) BFP!!!
June 26th, 2010 - Beta #1 : 531
July 12th, 2010 - U/S : HB 127