Peggy,
Lots of sources for th adapter. I mainly use the pro versions at fotodiox.com or Haoda's AF confirm adapters. These adapters allow the AF system to be activated so that you get the normal viewfinder indication of good focus once you manually adjust the lense correctly. If your Leica lenses are R versions then a lot of them will work. A few have interference problems with the mirrors on certain EOS bodies.
Here is a wonderful source to check compatibility.
http://www.pebbleplace.com/Personal/Leica_db.htmlI am currently using the following my 5D: 50/2.0, 60/2.8 macro, 90/2.8, 135/2.8, 180/3.4 APO, and the 560/6.8. These all clear the mirror of my 5D.
