I'm flying out to Italy in the morning but before I go to finish packing I wanted to quickly point out something that I took for granted. If you use Visual Studio to edit your .wxs files Scott Weinstein has a great blog entry that clearly articulates how you can get VS to syntax highlight your .wxs file (as XML) and provide IntelliSense while editing.
Personally, I use VS when spending lots of time editing .wxs files and use notepad2 (for XML syntax highlighting) when just doing quick fixes to a file. It is amazing how much typing IntelliSense can save you and I've found syntax highlighting really cuts down on the number of silly mistakes I make in XML (for example, missing the close quote or close angle bracket on an element).
When I get back from Italy (in a week) I'll try to get the hour long WiX presentation I did internally a couple months ago up on the WiX SourceForge site. That presentation is a much more detailed version of the 45 minute presentation I gave at OSCON. After that, maybe I'll post the entries from the Travel Diary that I'm taking with me to Italy.
Arrivederci! Colloquio a voi la settimana prossima.