If you want to use a free ad server solution then here is an OpenX review and a tutorial (including video). OpenX powers over 30,000 publishers which decided to manage their advertising needs. Its competition is Google AdManager, Doubleclick, 24/7 Real Media, Right Media, Valueclick, Adbrite, Advertising.com and others...but OpenX is free.
Openx is also easy to use. we are also using openx. if you have any doubt in openx installation and upgradation we will help for that. we will give training how to use openx. for further details please visit our website adserverservices.com