Dear me, I appear to have become London.pm travel czar.
For YAPC::Europe I recommend staying at: CAB INN Scandinavia. The rooms are very small and it's a few stops from the venue. But it's very practically CHEAP and closer to the center of town so you can spend more on Carlsberg and smørrebrød.
We can fly using SAS:
12 Aug 2008 LHR 20:10 -> CPH SK1508
17 Aug 2008 CPH 18.15 -> LHR SK1507
It's quite far ahead, but at least you have some plans now