The Vista Upgrade Advisor - available from microsoft.com will tell you if
your current hardware is Vista capable/ready, and probably advise you of the
recommended edition of Vista which will run on your current hardware. (I
don't know if that's what you want as far as your question is concerned).
I believe the minimum requirements for Vista Basic is at least 512meg RAM
(1GB recommended) Pentium IV or equivalent CPU.
Whether your perhiperal hardware or expansion cards will work on Vista
that's another issue; you should visit the various manufacturer's websites
for info on Vista driver availability, download and accmulate these - e.g.
burn the files to CD/DVD so they are easily at hand if/when you install
Vista. Bear in mind, newer hardware will be more likely to run under
Vista. Anything "Made for XP" for instance.
I'm not sure what you really mean by "what all the different pieces do".
Can you be more specific with your question?
Eg if you have a Canon printer, visit
www.canon.com for downloading their
latest drivers.
Older printers might not be supported - and I don't know how long is
considered "old" as far as hardware is concerned eg a 10 year old printer is
"old" but even a three year old printer might be old, at least anything made
before the release of XP. So "Made for XP" hardware I guess, would be more
likely to work with Vista, if you obtain the correct drivers (if they are
not on the Vista installation media).