Is there a minimum amount of time a credit card company has to give
you to pay your credit card to avoid a finance charge?  My credit card
company closes the "accounting period" on the 23rd, but does not mail
my statement until the 2nd of the following month, with the payment
due on the 12th.  By the time I get the statement, even if I write a
check the next day, it usually arrives late, and then I get assessed a
finane charge.  This does not seem fair or legal.

Beat them at their own game.  

- Open a free checking account with free online access (or use your
existing checking account if comfortable enough)
- Get your routing # and your ?FULL? account number
- Make a deposit into the account covering the average credit card monthly bill
- Sign up for the online payment feature with your credit card
company. (if your company does not have one, it?s time to move on to
another CC company)
- Add your checking account to your credit card payment account using
your routing and full account number
- Pay off your credit card every weekend in full.  


If you do the above, they cannot charge you ANY finance charge. 
Legally, you have about 29 days (look at your contract) after the
transaction before they will/can assess finance charges.

Well, my question is more focused on the amount of time there must be
between when they MAIL a statement and when the amount on the
statement IS DUE.  If the time is too short, they will ALWASYS get
their' freakin'ly outrageous finance charge becuase there is not
enought time to pay by mail.

Does anyone know if there is such a minimum?

I can't give you an answer as to minimum time.  But I did have the
same situation which proved embarassing more than once when I thought
there had been time to get the payment posted.

While policies differ between credit card issuers, and there are no
promises here, I simply asked them to change the 'due date' and they
did.  End of problem.

Have you tried that yet?

Digs