The enigmah switch software is on the slayer disc, which will install it and the new dashboard
I put some BIOS files on the ftp server that has the slayer disc, that are compatible with Xbox versions 1.3 and earlier, if you have one of these boxes you will get more from your chip by using one of those bios files.
Cromwell only allows you to boot into Linux on your Xbox, and provides a simple means of flashing your chip using a CDR with a bios.bin file on it.
If you have a 1.4 or 1.5 Xbox, then I don't have any bios files to help you out with, but this will thell you which you need
http://www.xbox-scene.com/bios_retail.html
This is also very relevant, and points you to exactly where to look for the newer bios files, and what to do with them.
http://www.xbox-chipz.co.uk/x-ecuter.shtml
Update your bios, use the slayer disk, and take the relevant option for your xbox from the menu (probably D for you)
This will install and configure all the applications onto your xbox and allow you into Enigmah's video switch software (you get an apps option in the new dash)
Once the video option is switched to NTSC, AND you have the hi-def pack attached you get the option screen to define what your display is capable of (upto 1080p).
This setting will persist after the modchip is switched off, however, rumour has it that XBox live will have a new "patch" to detect xboxes that should be PAL, and have NTSC settings and will then ban you.....
If you plan to use live, you should be aware of this. I don't, I use this instead
http://www.xboxlink.co.uk/
As for game support, every PAL game I've put into the xbox since I switched the video settings outputs a progressive signal at 576p. (Halo, MotoGP 1/2 PGR 1/2 etc...)
You should have had a PM from earlier today with new info for the Slayer disk I put on the ftp server for you.