NOTE: This is quite out-of-date. You should be using SystemImager 3 or later. It has the e1000 driver built in, as well as many other nice features.
Below is a link to a Systemimager .iso which should work with the Dell PE1650. I couldn't make the 2.4 kernel fit on a 1.44MB diskette, so you'll need to burn it to a CD (I use mini-CDs.) It has the Intel e1000 driver loaded as a module on boot.