Upgrading the ROM on your HTC Wizard is a relatively simple task, but there a few things you should do before attempting to do so.
When you upgrade your ROM, your device will be completely wiped. That includes all software, all data, and all settings. If any of those are valuable to you, you should make sure that you save it in a safe location.
The easiest way to save your calendar items, contacts etc., is to sync them to your desktop PC. You can simply set up a fresh sync relationship after the ROM upgrade to get the data back on your device.
Software and settings are a different story. To be able to backup and restore those, you need special backup software. Pointers to good backup software would be appreciated. Please be aware that restoration of backups made on a pre-AKU2 ROM may not be possible on a device loaded with an AKU2 ROM version.
Now that you have all your valuable date stored in a safe place you can start upgrading the ROM. If you try to upgrade for the first time, go for an upgrade with a RUU version. This an executable file that you can simply start from your desktop PC while having an ActiveSync connection active. Just follow the directions on your screen and you'll be good. All ROMs currently available here on the HTC Wizard Web are of this type.
Please note that you should CID unlock your device if you want to use a ROM that was not released by your devices manufacterer.
When you want to upgrade, please make sure that your battery is fully charged. A failed ROM upgrade can be remedied but that takes a lot more effort, so you don't want your battery to give up on you at 50% of the upgrade proces.
The total upgrade proces should take about 10 minutes, and might appear to stop a few times. Don't worry unless the process takes well over these 10 minutes.