DigitalPoint Network is a free advertising network system(Links exchange rotation). You add some code on your weblogs and text links from other sites in the network are displayed. You also add your text links which will be displayed in the network system. Currently the types of any websites that can use it are ones that do server-side processing. This includes : vBulletin forums, phpBB 2.x forums, Movable Type blogs, Blogger blogs or any site that supports PHP, ASP, PERL, cold fusion, etc..
Weblink : DigitalPoint Network