OK here you go 
I have modified the forums as per my post above. The way it works is this. I set up a site (ie: Dom’s “Games & Casino” site) in a lookup database, assigning it a code (in this case 1001). Once i give Dom her code, she sets up a text file on her server containing links to all her banners or as many as she wants rotated. She also provides me with a logo.
I’ve set up a demo (Dom – as i cant access your server, you link to http://www.casinomatcher.com for now so dont be surprised!). There are 3 example banners i created in the loop which are in a text file over on my casinomatcher server for now (http://www.casinomatcher.com/1001.txt if you want to see it) but would obviously normally be on Dom’s server so she can constantly update it without hassling me 
I also set up a simple Text logo for Games & Casino which i run from the forum server.
So you go to the forum with a parameter which is Dom’s site ID i assigned thus:
http://www.oggs.com/pokerforum/index.php?rf=1001
(Contrastingly you can go in via my own link at
http://www.oggs.com/pokerforum/index.php?rf=1000 to see my banners/links/logo etc)
That will rotate her banners, show her logo and add her website and links in the relevant places. It sets a cookie that remains for 24 hours or until it is overwritten so that user will see her banners/links etc for that time, even if they return later.
This ID is passed to all pages on the site. Note i have genericised the Forum name to “The Online Global Gambling Symposium” so the user sees this tag however they enter, it relates to the domain name (OGGS) and should thus allay multi-site marketing fears hopefully.
The beauty of this sytem is that you can also enter at different levels (although they can navigate back up the tree, however still with your banners/links): For example, if you just wanted your users to go to the Poker forums section, you link thus:
http://www.oggs.com/pokerforum/index.php?c=2&rf=1001
…or if you wanted to go straight into one specific forum then try:
http://www.oggs.com/pokerforum/viewforum.php?f=2&rf=1001
…or maybe straight in to a specific Post:
http://www.oggs.com/pokerforum/viewt.php?t=11&rf=1001
As far as you guys are concerned, all you have to do is give me the basics (URL, Site Title), get assigned a code and create a text file of banners before you link over. If you are happy with the Text style logos, i can do that for you, else i can give you a little template to add your bits too.
NOTE: I’m not quite ready for people to go piling in yet as a) i want your feedback on this first so it’s 100% right before rolling it out and b) I want to make sure everyone is clear about who gets what out of this and responsibilities. I dont mind doing all this gratis but I’d like to have some sort of benefit out of it that people consider fair. Actually BB1’s idea suits me if thats considered reasonable by others
Cheers
Simmo!