The latest comScore numbers (via Ars Technica) are out for U.S mobile market share, and they reflect some huge gains for Google’s Android platform, along with significant losses for Palm. The data covers mobile usage from September 2009 to December 2009 — so it gives us a sense of how the holiday season went but doesn’t include major launches from this year like Google’s Nexus One phone, or Palm’s recent jump to Verizon with new phones.

Here’s the rundown: Google gained a huge 2.7 percent of the market, moving from 2.5 percent in September to 5.2 percent in December. Meanwhile, Palm fell massively from 8.3 percent to 6.1 percent over the period. Both RIM and Microsoft lost one percent of market share, with RIM dropping from 42.6 percent to 41.6 percent, and MS from 19 percent to 18 percent. Apple gained 1.2 percent overall, jumping from 24.1 percent to 25.3.

Google’s significant gains can likely be attributed to the release of the Motorola Droid and Droid Eris phones on Verizon, along with the ingenious marketing campaign that introduced those phones to the public. The increased Android and Apple presence probably drove down Palm’s share, and it also didn’t help that Palm was practically silent for the second half of 2009. Similar factors likely led to Microsoft’s losses, along with the fact that its most recent Windows Mobile update was a bust. RIM obviously couldn’t keep up with its sexier smartphone competitors, and Apple continued its steady gains.

At this rate, I wouldn’t be surprised if Google ends up overtaking Palm in the next numbers. The Nexus One has garnered a ton of buzz in a very short amount of time, and Palm couldn’t really compete with its minor Pre Plus and Pixi Plus hardware upgrades for Verizon. With the Nexus One coming to Verizon in spring, along with constant news of upcoming Android phones, Android will definitely overtake Palm’s market share within the first half of 2010.