A lot of girls in the weddingplans community on LiveJournal needed a program to conduct their online RSVPs. I did a little poll and the most popular choice was for me to write a plugin, and so I did!
Download the RSVP Plugin V1.0 (still in beta, but tested in Wordpress 2.5.1, 2.6 and 2.7).

Guest Interface:
-guests go the the url provided in the invitation or click from the wedding website
-guests are asked to select their name as it appears on the RSVP card instructions (has to be unique for each guest so it can match to something in the database)
-when a match is found, it takes the guest to a new page with a form :
name: _____ dinner selection (drop down) for each
and finally
comments: (text box)
-once the form is submitted, the guests for that party are added to the database with their RSVP information

Bride’s Interface:
-form to input guest party name (last name) and max number of people invited for that party
-shows list of guests so far with dinner selection, who RSVPed or not, comments, total head count, total meal count…

Installation Instructions
1. Upload the RSVP directory to the `/wp-content/plugins/` directory
2. Activate the plugin through the ‘Plugins’ menu in WordPress
3. Place php call in a new page template. An example template is included.
4. Create a new page using the template and add whatever information you would like. The guest form shows up in this page.
5. Link to the RSVP page from a password protected page.
6. RSVP Admin panel is under “tools” and “settings”