Use the /h switch to hide the client. So if you made a shortcut (a lot easier than typing it each time. 🙂) it would look like:
"C:\Program Files\SETI@home\SETI@home.exe" /h
Obviously, the file names are wrong, but you get the point. 🙂 And yes, for some reason, the quotes are used in a shortcut. So basically, make a shortcut to the client, go into the shortcut properties, and add a space and then /h
Now for the queuing programs...I know of NO way to hide SETIQ. You could use a program like Trayer to maybe hide it, but the program won't do it, itself. I believe SETIDriver will hide itself in the systray if you want it to. And, although I've never tried the program, supposedly under Win9x, SETIHide will totally hide itself.
Hope that helps! 😀