Here's another one that pops up again and again so I wanted to post a quick note on it. Many people fight the issue of getting client push installations to work for ConfigMgr 2007 clients in a workgroup environment only to find out hours or days later that it's just not supported. It's kind of easy to see why because this little nugget is buried pretty deep at http://technet.microsoft.com/en-us/library/bb680717.aspx but if you look hard enough you'll see that it says:
"The client push installation method is not supported for workgroup client installation."
So now hopefully if you find yourself in this position you won't waste too much time trying to figure out why it's not working. In addition, here are the other support limitations you run into when operating in a workgroup environment:
J.C. Hornbeck | Manageability Knowledge Engineer
How to Autodiscover Workgroup Machine Via SCCM 2007 r2 & R3?