Copy data from one field to another field on same form

[Rob]

I have a form that is used to enter member information (name, addr, etc).
We have a lot of organizations that start with same name (usually state
name) so instead of getting a list of 50 "New Jersey ......" I decided to
create an "Alpha Sort" field that would allow the user alter how the name
sorts (used in reporting, etc). So here is the problem, I would like the
form to auto fill the organization name from OrgName field after OrgName has
been entered but before data is saved. If a user wants to change Alpha Sort
that user can overwrite the default of OrgName.

I tried a few different things and none see to work?? Any suggestions out
there ...

thank you in advance,
rob