She will place her preference on her website.  Be sure to read her entire site for this information.

Kate

Always place the donation in an envelope.  If she's coming to you, leave it in an obvious place before she arrives.

If you're going to her, leave it on a table when you enter.  In both cases, motion towards the envelope and say, "That's for you."

Don't hand her the envelope and don't mention money.

-- Modified on 6/5/2006 2:16:23 PM

The only thing I could add to the previous comments is that you might not want to actually say anything, but make sure she sees you take the envelope out and put it in the place she's indicated.  Eye contact with her can serve to confirm that yes, you both know what's in there, but in case someone is listening who shouldn't be, there's nothing for them to overhear.

She'll probably have some information on her website about how she prefers those matters handled.  Go along with her requests in every detail, even if you think she's being overly cautious.

Be prepared to have her excuse herself into the bathroom to check the total.  It's sad to say it, but some guys will intentionally short an envelope, hoping that the lady won't count it until after they've left.  If (God forbid) it turns out you miscounted when you filled the envelope, don't argue, just make it right.  Apologize profusely if that happens, too.