Clean Your Dress
Even if you're undecided about whether to preserve your dress, have it cleaned ASAP. The sooner you get it cleaned, the more likely it is that the stains will come out. If you do decide to have it preserved, be prepared to spend anywhere from $100-$500 (or more). Many local dry cleaners can take care of this for you—I paid a little over $200 for mine. If you don't feel comfortable using your local cleaners, the store where you purchased the dress may be able to help... for a price. I purchased my dress from Kleinfeld, and they charge $500 for cleaning/preservation.
Schedule Your Thank You's
As soon as you get back from your honeymoon, you should get started on the thank you notes. To avoid getting overwhelmed, first figure out exactly how many you need to write. Then divide that over a week so that you're just writing a few per day. And don't let your husband off the hook here—enlist his help for his side, even if his handwriting is worse than a kindergartener's. His family will appreciate the effort anyway!
Announce Your Marriage
Send in a wedding announcement to your local newspaper. This will make a nice keepsake for you and your families. Ask your photographer for permission to use one of the pro pics if you did not purchase full rights (check your contract!).
Review Your Vendors
Loved your venue, hated your DJ? Help out other brides in your area by posting reviews on weddingwire.com. A lot of vendors, especially independent ones, rely on word of mouth to book more jobs. But be careful: Even if you hated your photographer, wait until after you've received your album to post your scathing review.
Change Your Name
If you're taking your husband's last name, get the ball rolling as soon as you get home from your honeymoon. The longer you wait, the harder it gets—I've been married four months now and have just started the process of changing it, even though I started using it unofficially right after the wedding. Hey, there are a lot of forms to fill out!