Black Sun Over Midland - This is a fairly comprehensive site. It's got the best collection of screen shots from the anime and most importantly ... it's still up and running. (most of the other Berserk sites I've found no longer exist)
Arctic Nightfall's Berserk Site - A very well done site that just recently went up. The message boards are also informative and generally pretty funny.
Skull Knight - Another new one (it's not a new site, it just took me an inordinately long time to discover it). Good translations, very international-flavored message boards, and the author seems to have something of a Griffith-bias (not that that's a fault of any kind).
A bit from the Ask John Archives on Anime Nation's site. An especially well written response to the question: Why is Berserk so good?
WinAMP Skins
Griffith - It's Black&White and pretty minimalistic but everything's skinned and it all works properly.
Judeau - It's my second attempt at this whole skinning thing and I think it came out much better than the Griffith one.
Manga Translations
There is a wonderful Berserk Translation Database put up by ranemaka13 that has very accurate translations, and seems to be progressing nicely. The only thing I can add is a weird copy of Volume 6. It's pretty piss-poor English and skips a lot of dialogue, but it's better than nothing ;)
There is also this page on the Skullknight site. Different organization and it's more frequently updated.