If you're still yet to buy the speakers, why not simply invest in some wireless ones? I'm not sure if your budget is £200 or if you meant you didn't want some guy trying to sell you a set for £200. But FYI you can get a pretty nifty wireless 5.1 setup for around £200.
I used to use the Logitech z906 system which is wireless and probably around that £200 mark now, but just recently had to downgrade to my old z10's for space saving reasons.
In regards to your "special type of cable" question, as long as the output on the speakers is a 3.5mm jack (or obviously, USB) you will have no problems connecting them to a PC.
EDIT: The z906 is indeed around the £200 mark
if you're interested.