SQL Updates with Parameters problems : HELP!!!!!

I've been doing fine running Select queries and passing parameters at
runtime, but I can't seem to get a clue about executing Update queries
with parameters.  Can anyone point me in the right direction?  Do you need
to use a TUpdateSQL component?  How about parameters?  Basically I'm
trying to change field values with calculations based on other field
values and runtime passed parameters.  Can a TQuery do this?  Can't seem
to find any examples.
Any help at all is much appreciated.

Scott Paterik