http://digital-photography-school.com/m ... rmat-dslrs

The greatest object of lust in my life at the moment is the Mamiya 645 AFDII. Options of shooting either film or digital with a change of the back.
*sighs*
Someone needs to do that for a 35mm body.

What's the difference with medium format?

I don't really understand the whole thing.

Is it a different size of film (in the analogue world)?

If so, what's the poiint of it in digital when you can crop an image to look the same?!

What am I missing?

http://en.wikipedia.org/wiki/Medium_format_(film)

Essentially, it's larger than 35mm, and more square in aspect.

In many folks eyes, MF still looks better than a lot of DSLRs out there. You'd have to be at the high end to produce equivalent or better results (all things being equal, ISO etc.).
Clicky for a book all about it.

Basically, it's a gorgeous format, still used by a lot of pros. It requires much more thought and attention to use well, but when it's good it's wonderful.