I use the RJ Camera adapters for all my micro 4/3 mount stuff (except for my FD adapter, which I can't remember off the top of my head). Basically I paid about $25 for all of them. I have EF, Konica, Minolta MD and Nikon adapters, and then I use OM to EF stacked with the EF to m4/3 for my OM stuff. (just because I had it already).
You might want to start with "el cheapo" generic adapters from eBay, and then buy something better for the "keepers". For SLR mount lenses, I prefer Fotodiox Pro adapters, with no focus confirmation chips. My EOS to m43 adapter was also RJ Camera. It's well made and it did a fine job. I don't use m43 any more.
