Penttax 50mm 1.7 lens on Canon body (400D/450D)

Hi,
Whilst playing with camera / flash at the weekend I found my old Pentax SLR, which was originally my fathers until he upgraded to an EOS10 and I shot with the Pentax... anyway...
I found the 50mm 1.7 lens which I was told came with the camera, although I can't remember ever actually taking a photo with is as the two zoom lenses were always more useful on holidays. (Bear in mind this was when I was around 8-11 years old and hadn't found this forum or learnt the relevance of primes. (I'm now 25 btw)
Currently I'm awaiting delivery from HK an adaptor to try it on my 400D, but until this arrives I was wondering if anyone has done anything similar to this and indeed if this could be a way of using a fast prime at a much cheaper price than the Canon lenses.
On the down side there is the manual focus / manual exposure, but the cost (ebay currently has a 1:2 lens for about £35) this may be worth it.

There's quite a few POTN'ers using MF lenses with Canon bodies. Check outthis thread for info and sample pics. It's a bit of a learning curve getting your focus spot on (especially with the small viewfinders in the crop bodies), but they're a lot of fun to play with and if you're choosing the right lenses can give you some very nice results.