You can get the entire BLAME! series off of www.omanga.net. If that's down, try using Bittorrent to download it off www.torrentreactor.net. Manganews has some links which they occasionally update:
http://www.manganews.net/show.php?title=29.
Failing that use the directconnect (DC++) swarming application and hit some manga hubs to find it yourself.
Biomega is supposed to be done by omanga.net but it was down last time I checked. It's the latest work by Nihei and bears a close resemblance to Blame. I managed to get a copy from the Evil Genius scanslation group here:
http://evanidus.ath.cx:7421/.
Is Heen's Blame forum down for good?
That's all the news for now, if anyone has anything interesting to add, please do.