GPU overclocking tools

With these tools it is possible to change the clock speeds of Radeon graphic cards to increase hashrate and thus mining profitability.

Usually core clock is increased and memory clock is decreased to lower temperatures and save power.

Windows

AMD GPU clock tool - GUI / command line, http://www.techpowerup.com/downloads/1128/AMD_GPU_Clock_Tool_v0.9.8.html
AMD / ATI Tray Tools - GUI, http://www.guru3d.com/article/ati-tray-tools-/
ClockTweak - command line, not free, multiple cards, http://forum.bitcoin.org/index.php?topic=9982.0
MSI Afterburner - fancy GUI, multiple cards, needs to be unlocked, http://event.msi.com/vga/afterburner/
RBE Radeon BIOS editor - GUI, can also be used to overclock, http://www.techpowerup.com/rbe/
Sapphire TriXX - fancy GUI, multiple cards with crossfire only?, http://www.sapphiretech.com/ssc/TriXX/