Domain registrar.

Anyone recommend a good cheap one? It's to get a couple of names transferred to from somewhere quite expensive.

I use - cheap but very limited service, best for those comfortable with the workings of DNS. I host the domain's nameservers myself and only use them for registration.
I normally use UK Reg. They're cheap for .uk domains and reasonable for .com's. I've never had a problem with their service either, which is more than I can say for the previous company I used.
They fall firmly in the "thieving fuckers" arena for me, having conned me out of £180 by screwing up a bunch of .info registrations, changing their rules behind everyone's backs, and denying all wrongdoing. is the one I've got most of mine with. Haven't shopped around much tho'.
I use . Others curse their name, but I've found them cheap, on-the-ball and the tech support email appears to be answered by actual humans with clues. You can also do everything to your domains by web form.
I encountered them fixing up arkady's domains. One was through, who are utter, utter arseclowns and comprehensively prove that you don't just go for the cheapest one.
One of the guys I hired used to work for UK2. He has some interesting comments to make ;)
Indeed, they are not. I believe their domain registration service is offered more as a convenience to existing hosting customers who want to have all their invoices come from the same company, rather than something attempting to compete with the cheap registration companies.

Still, if you want hosting too...