sapper, hope I'm not too late but you don't have to go back to Windows. I play Team Fortress 2 competitively on Linux so I have a lot of experience installing Steam in Linux. I am actually working on a complete guide for Source in Linux through Wine which covers the installation of Steam and Wine. I take a slightly more advanced approach at setting up Wine and it would really help me to have someone (who isn't me) try it out and give me feedback so I can see what parts I need to make more clear.
I took my original, cut out the Source parts to better fit Half Life and attached the file to this post. Check it out and if you have any questions post back, I'll be sure to keep an eye on this thread.
EDIT: If you were by chance referring to Half Life 2 and just left out the 2 part in your original post use the guide I posted here viewtopic.php?f=47&t=39199
instead. Half Life and Half Life 2 are two very different games.