Can you recommend a training company that offers DHTML and/or XML courses?
I unfortunately can't make a specific recommendation because of the nature of what I do, but I can give you a few pointers. Don't expect to find a lot out there yet on XML. The technology is changing at such a rapid clip that much of what may have been valid even six months ago is no longer true. I expect that with the release of Internet Explorer 5, and later Navigator 5, that may very well change. Also, take what you do find in seminars about XML with a certain grain of salt for much the same reason. It's poised to become the next "big" thing (and for good reason) but there are a number of companies who may be promoting it that won't take you beyond the basic syntax level (which at its core, isn't much different from HTML).
Finally, if what I see at Microsoft is any indication, there will be a fairly extensive market in courses aimed at creating behaviors or Web components within the next six to nine months, as it becomes increasingly possible to build interface elements for full blown applications using DHTML.
Hope that helps.