I thought I would post this since I just got the e-mail, but the latest Lake Books mail bid sale has been posted at their site:
http://www.lakebooks.com/current.html. I have dealt with them before (it's where I bought my Overton book), and they have many books that are tough to find, out of print etc. for US and world issues as well as stamps and paper money. They also have extensive auction catalogs as well, so check them out and you might find a book you have been searching for. They are still somewhat old school, but at least now you can e-mail your bids!