You name the algae bloom, and I probably got it at one time or another... =)
Like daveedka discovered, the easiest way to rid yourself of a nasty algae bloom is by completely cutting the light off from the tank.
If you are battling a nasty algae bloom and tank to try the blackout method here's what to do:
1.) Clean out your mechanical filters, and do a 40-50% water change.
2.) Raise spray bars, add airstones (with air pumps attached to them), etc. to increase surface aggitation.
3.) Cover your tank with something that will not allow light to enter the tank. A heavy blanket will work, but when I tried it, I preferred black garbage bags... that way, I won't have to deal with a dirty/smell blanket afterwards, and I can reuse the garbage bags.
4.) Depending on what kind of algae bloom you have, wait 2-3 days. During this time, don't feed your fish, and don't let any light get into your tank... don't worry, you're fish will be just fine.
5.) After the waiting period, remove your cover(s) do another 40-50% water change, and clean out your mechanical filters again.
6.) Make sure you take steps to prevent another algae bloom. The blackout method is more or less a "reset" button for your tank. Its not something you want to do often, but it will give you the opportunity to start "fresh" again.
This method works for both planted, and non-planted tanks. For planted tanks, just dose with fertillize after the black out is done. The plants will survive, though more fragile plants may suffer more than hardier ones.
HTH
-Richer