perl question

I am working on a script that takes a email message
that is piped to it from a dot-qmail file. After reading
through the file, I have
created a hash of which the values are to be inserted
into a MySQL db. Problem is, the keys do not coorespond
to the field names in the table.

Could someone help me run through this hash and "remap"
the keys to a differant value?

For instance:

First_Name => Joe
Last_name => Smith

needs to become

fname => Joe
lname => Smith

v/r
Mike