Tweetup, the Twitter advertising startup from Pasadena’s Idealab, said on Tuesday that it has acquired Twidroid, which has developed a popular Twitter application for cell phones using Google’s Android operating system.

TweetUp, backed by Steve Case’s Revolution LLC, First Round Capital and Internet entrepreneur Jason Calacanis, said the acquisition includes popurls, an online site that aggregates the most popular items from Twitter, Digg, YouTube, the New York Times, and other news and social media sites.

TweetUp’s ad service allows Twitter users to buy higher placements of their tweets within searches conducted on Twitter and other search engines, such as TweetDeck.

“Acquiring Twidroid provides TweetUp with a number of strategic advantages,” said Idealab Chief Executive Bill Gross. “Twidroid is widely considered the best Twitter (application) for Android phones, and it leads in market share.

TweetUp said it will rename Twidroid to Twidroyd, to minimize confusion with products from Lucas Films, which owns the trademark “droid.” Financial terms were not disclosed.