Can you buy unthreaded BB's

got a bad feeling ive ruined the threads whilst fitting it

erm how would they work? you may be able to re tap the threads.

Yes you can!
UTFS.

what mack said

the cups thread onto the BB cartridge instead of into the shell

Search for YST Threadless Bottom Bracket on eBay...

im not certai ive ruined it, not ridden it yet. tutorial i was watching said it should screw together easy, and it was very hard work

There are several options:

1. With special tools, a frame builder can ream the inside of the BB shell, braze bushings in it and cut new thread. By farthe most complex and expensive method, because you need to re-paint (a part of) the frame.

2. If the frame had BSA/English thread: just run Italian thread cutters. A good bike dealer has them. Italian thread has a larger diameter, so you can cut it in ruined BSA threads.

3. Use a BB set of e.g. Stronglight, Mavic, or the like.
   Some very good dealers have the tools and it's possible to get the BB sets, however it's not going to be easy. The special tools are necessary, becuase you have to cut a 45° taper on both sides of the BB shell.
   As far as I know, it's only available for square taper BB axles.
   Extra feature: the chainline is adjustable.

4. Google gives this, but I don't know these:

http://www.stylefeeder.com/i/t3mf9pjw/Bottom-Bracket-Set-68x116-Square-Threadless-F-Repair

http://www.tritoncycles.co.uk/products.php?plid=m13b199s110p3339

http://www.yst-corp.com.tw/new/cartridge_bb01.html (ISIS and square taper)

im not certai ive ruined it, not ridden it yet. tutorial i was watching said it should screw together easy, and it was very hard work

Go to a good dealer and ask to chase the threads with proper taps. Perhaps you can save a lot of money.

i've seen special bbs, without threads, on ebay. too lazy to look for it now, but i'm sure i've seen it!

if I recall correctly, it had a thread on the middle of the shell, and one side screwed to the other

This could be a solution?

http://cgi.ebay.co.uk/Btm-Bracket-liner-for-stripped-frame-special-lockring_W0QQitemZ390018823946QQcmdZViewItemQQptZUK_sportsleisure_cycling_bikeparts_SR?hash=item5aceeef70a&_trksid=p4634.m333.l1262

there you go son.

http://prollyisnotprobably.com/2009/07/threadless_bottombrackets.php