Most important thing potential Dvorak people need ....

Even though Windows has built-in Dvorak an onscreen keyboard is vital.

http://www.clabs.org/blogki/index.cgi?page=/ComputersAndTechnology/DvAssist
has a good one and a good switching utility BUT it does not play well
with Windows 7.

When I am at Qwerty at work or a friend's home I need an onscreen
helper to know where to position my fingers. At home I have a dual
labeled keyboard -- and I can type Dvorak on it but ironically never
can type Qwerty on it.

I love DVAssist when on Qwerty keyboards so I can do Dvorak but it
does not play well with Win7 which will be the one most XP Users
switch to over next few months and years (Vista flaws are mostly gone
in Win7).