I think this was discussed the last time I posted my setup in here - but all I did was download the image from the photographer's website, photoshopped out his name/logo (Dean Belcher) and then used a programme called 'Rasterbater' to blow up the image.
You don't need to use something like that, but what it does is create its own dotty artifacts when blowing up an image, rather than JPG blocky nastiness. It works really well. Then, I just took the finished image to a printers, and got it printed for £10. Well worth the money if you ask me.
The original is on his website but I think I've got the image on a drive somewhere, if it's not hidden somewhere on this thread already - let me know and I'll get it to you.
Success is merely a failure to imagine more