Sprint today launched a series of customized online ads showcasing its Now Network. The spots feature interactive home page takeovers tailored to the specific audiences of various sites, beginning with Yahoo! and expanding to AOL, ESPN.com, WSJ.com, People.com, CNET and YouTube throughout the following week.

The campaign also includes custom placements on MySpace, Pandora, Gawker, FoxNews.com and Reuters.com, all of which feature ad banners containing feeds of readership-tailored data from the Sprint Now Network site.

Through a string of online placements, Internet surfers will be encouraged to engage with advertisements that provide real-time information through widgets. For example, YouTube’s home page takeover will feature a user-generated clock where users can film themselves for three seconds while holding up a pre-assigned number, serving as a digit on the Now Clock.

Other notable widgets include a Twitter word search that lets create their own flock of Twitter birds, Now e-cards that self-destruct after one second and tiny construction workers chirping on their Nextel Direct Connect phones with a counter showing how many people are using those phones at the moment.

The new campaign comes as Sprint ramps up for the release of the much-anticipated smartphone, the Palm Pre. Sprint has obtained an exclusivity deal with Palm to carry the new device