Detecting a users first visit to a website using codeigniters session library

[eluser]jsfmills[/eluser]
Codeigniter session problems is resolved for internet explorer but still create problem in WAP.I'm pretty new to codeigniter, but not new to frameworks.I've tried them all and I find codeigniter to be the best overall.Keywords in the URL now have only a very minor impact on the search results, if at all.