i looked into this as well, and invested heavily in being able to perform this functionality. In short what you are trying to do is allow the public to reserve a resource (time slot) that is backed by an asset (speaker) this is the exact opposite than what ubercart will do as uc allows one to purchase an asset only. it can be done, and lots of people are asking for this, I am in the process of writing a fully functioning module that will do this, but it is still a few months out.

here is a perfect example of somebody doing the same exact (though their captcha seems to be broken
http://www.beauty-indulgence.com.au/make-booking

here are some other notes
http://drupal.org/project/planyo_reservation_system
This is hosted off site and is subscription based, the features are severly lacking and it looks like crap

http://drupal.org/project/uc_hotel
didnt get to see or test it out, but this seems to be the one that most folks speak about on various forums

http://drupal.org/project/simple_reservation
again, cant test/see it, but its out there

http://drupal.org/project/rooms
all it says is coming soon, built for drupal 7, so no idea what the functionality or look/feel will be like

http://drupal.org/project/agreservations
no info, but their description looks like it will fulfill a decent part of the reqs

On 12/28/2011 5:51 AM, Ayath ULLAH wrote:

Hi,

I have a team of individuals who are taking on public speaking opportunities. The idea is to create a site where the public can book them for speaking opportunties. The speakers should be able to set their own prices. The public should be able to ask for specific dates and times and once the speaker agrees the money should go directly to the speakers paypal account.

I am also planning to open the application out to other users but for the moment it'll be closed to the team of speakers I have.

Any modules/tutorials would be helpful.