At JimWorld, there is a discussion being lead by Barry Lloyd, a.k.a. MakeMeTop, on the topic of Site Match, pay-for-inclusion. The thread is named Experience with Yahoo Site Match?
Barry Lloyd, an experienced SEM, discussed his experience with Site Match. He said on average you need to wait 4 business days for editorial review. He points out that the reviewers do not always review the pages submitted, they often look at other pages that were not submitted including a contact information page. So the reviewer is looking for the "integrity of the site as a whole."
After the pages are accepted, you will normally see them included within 12 hours. MSN/HotBot results vary from Yahoo! Search's results, in fact Barry has noticed a 5 - 7 day period of time where positions in Yahoo! are much lower then in MSN/HotBot. After the 5 - 7 day period the results improve "dramatically."
Barry and an other JimGuide make a point to watch out for "spam-like" pages. If the reviewer finds anything that resembles such pages, you will likely not get listed.
Good luck with your PFI campaigns and Overture's Site Match.