Use the RootzWiki instructions.
After copying each img file, create a file with the same name and append an .md5sum extention to it. In this file, copy the MD5sum number from the web site, followed by two spaces and the img file name. Save the file, then run
md5sum -c radio.img.md5sum.
If fastboot sits at the <waiting for device> prompt forever, make sure your phone is in fastboot mode (power off, hold volume up and down and hold power until the phone vibrates–could be 20 seconds or so; in the lower left of the screen it’ll say “FASTBOOT MODE” in red). If you still get the <waiting for device> prompt while in fastboot mode, your permissions probably aren’t set up correctly. In that case run fastboot with sudo.