Google (NSDQ:GOOG)’s Android Market has crossed the 20,000 applications mark and is continuing to grow at a rapid clip, having nearly doubled in size in the last five months, according to a third-party portal.

A 20,000-app strong Android Market still puts Google well behind the titanic that is Apple’s App Store, but the progress suggests the Android Market is poised for explosive growth next year.

The 20,000 apps statistic comes from AndroLib, a portal and applications tracker that looked at the distribution of free and paid applications in Android Market and on Tuesday had the Android Market at more than 20,140 applications. Of those applications, about 62 percent are free and 38 percent are paid, according to AndroLib. Google’s Android Market saw the most software added in November 2009, around the time Motorola’s Droid smartphone was launched, AndroLib found.

Google CEO Eric Schmidt earlier this year suggested that Android’s growth would be explosive, and indeed, many of the fall’s hottest smartphones — from Motorola (NYSE:MOT), HTC, Samsung and others — run on the Android platform. Google itself has a Google-branded smartphone in the works called the Nexus One, scant details of which have started to emerge this week.

Most analysts suggest Apple (NSDQ:AAPL)’s App Store will hit 300,000 applications in 2010, with the Android Market expected to hit 50,000. In a presentation at the Raymond James IT Supply Chain conference in New York Tuesday, IDC Chief Research Officer John Gantz urged attendees to keep a sharp eye on how Google’s Android grows.

“Android is very distantly following the iPhone right now, but there will be some very interesting developmnts around the Google Android [platform] in the next 12 months,” said Gantz, who also predicted a “developer war like you’ve never seen” thanks to the number of mobile Internet users hitting 1 billion for the first time next year.

[via ChannelWeb]