I'm installing Untangle on a HP Proliant DL380 G5 with 2 GB RAM and 4 72 GB SAS drives configured in a hardware raid 5
I am not using the ISO install, instead I'll be using the install on Ubuntu desktop 8.04 Hardy. I would have posted the link except I have to have 5 posts before I can give you a URL. Look for that a little deeper in this thread.
I'll post my progress and problems here, and time permitting create an install guide.