Ajax is my next area to venture into. I have a little mod on my forum where I plan to try to figure it out. However, I don't think it would be useful in this case. Ajax is used to only 'rebuild' a small part of the page instead of the whole page and thus save on queries. In your case, you need to rebuild the entire table anyway which is most of the queries on the page.

Looks good so far, I'd like to know how to do this as well. :)