Thanks Charles, but I don't think that's quite what I want. Maybe I should explain it a little better.
I can set a variable to a color number by: (setq clr (acad_colordlg 2))
Then use that "CLR" elsewhere. What I want is to collect the linetype selected from the list and save it to a variable in the same way. I've played with a couple of things and can't seem to get a grip on it.