Updates to the Steam Client have been released. The updates will be applied automatically when your Steam client is restarted. The specific changes include:
Added ability for 3rd party Half-Life 1 Mods to have an icon in the games list, via an "icon" entry in their liblist.gam file. The icon filename is relative to games install directory and should be an uncompressed TGA 16x16 pixels in size.
Update - We have released an update to fix the %account% issue.