Someone posted a link to a place online where you could get a frame made up to suit for about £36 I think (may be in the scottish scoobies thread about this). Had planned on taking mine (pus sizes) to a local place though, 'cos I thought it might look better with a mount as well as a frame (ie certain thickness of card around the pic, then frame around that) which would be hard to guesstimate easily... would be easier done at a frame place.
Depending on costs, etc I'd probably just get it done there... if they were going to be OTT then I'd make sure I knew the size I wanted and size of mount so I could then order it online IYKWIM