Developers that have found success selling applications for the iPhone are showing great interest in applying their skills to the soon-to-be-released iPad, including more than a few music apps.

Flurry Analytics, which tracks mobile app development activity, found that 22% of the 20,000 mobile apps that went into development in the last two months monitored by its system were for the iPad. That’s more than the number of apps being developed for the Android and BlackBerry platforms combined.

When Apple flipped the switch on the iPad section of its App Store last night, some 2,000 apps were already created for the device ready for sale and download. In addition to the music-related apps Billboard reported on yesterday, this morning new details emerged on additional applications from such companies as NPR and CBS. The NPR app highlights all its member stations and programs. A built-in audio player allows users to stream audio from more than 1,000 programs—including its music series—while interacting with the apps other features, like photos and text-based stories.

CBS’ Interactive Music Group meanwhile released its app, created exclusively for the iPad, which compiles all of CBS’s Internet radio feeds from Yahoo Music, Yahoo, and all CBS Radio channels. It also includes photo galleries, charts and event listings.

Look for Billboard’s special report in the iPad and all things music apps April 9.

Meanwhile, there remains no shortage of iPad coverage circulating through the Web. Some highlights include:

Wired: The New Media Mall: What I’ll Be Expecting from the iPad
Video: WSJ’s Katie Boehret Brings the iPad to the People
CNET: What to Expect When Buying an iPad
Engadget: The Best Present and Future Alternatives to the iPad
BoingBoing: Why I Won’t Buy An iPad (and think you shouldn’t either)