I was being sued by a CC company's lawyer and I offered a settlement of less than the balance sought. Their lawyer said he would check with CC company. Now I received a letter stating

"Please allow this letter to serve as confirmation that you may settle this case by paying $780 by Mar. 13, 2009"
I am just trying to confim that this will settle this debt in full and not just to drop the case.
The Judge has my settlement offer written down to from the pretrial. I just want to make sure there are no loopholes they can get through before I send the check. Or should I do money order so they don't get my account #?

No the letter does not say it will show this as paid in full or that they are accepting this to settle the debt. He only said he will settle the case.

I would want the wording more specific in writing before I sent the money.

I agree the letter is too vague. I would send a counter letter

Dear Sirs:

In regard to the suit <insert court and docket number> I am offerring to settle this suit for a lumpsum payment of $780. Please sign a copy of this letter confirming your acceptance of this offer.

Acceptance of this offer will mean that, upon receipt of the payment, this account will be marked paid in full and all legal action pertaining to this account will cease. The Paid status will also be reported to the major credit unions.

That should do it.