New figures from mobile market analyst The NPD Group continue to show Google’s Android operating system leading the smartphone market, with Apple making gains and BlackBerry maker Research In Motion continuing to lose market share.

But while that might be a little “ho-hum what’s new” to most of us, the results also show that Motorola Mobility’s sales have been declining, which could be helped by its recently announced acquisition by Google.

Boy Genius Report has the story, which finds that Android currently holds 52 percent of the smartphone market as of the end of the second quarter of 2011. Second to Google was Apple with 29 percent of market share, followed by RIM with 11 percent and Windows Phone 7 at less than 5 percent. Meanwhile, though Google is holding its own with Android, Motorola slipped pretty substantially in Q2 2011. Here’s a quote from NPD’s press release:

Motorola’s overall mobile phone market share declined 3 percentage points, from 12 percent in Q2 2010 to 9 percent in Q2 2011. The company’s share of the smartphone market also declined from 15 percent to 12 percent. Motorola’s year-over-year unit share of Android OS sales halved from 44 percent in Q2 of last year to 22 percent in Q2 of 2011, as Samsung and LG both experienced financial gains.

NPD thinks closer ties to Android might help Motorola develop an edge over the Android-based competition of the likes of LG and HTC, which have been making gains at its expense. Google has admitted that the acquisition was mostly about Motorola’s several-thousand-strong trove of patents, which it’ll use to defend itself against lawsuits from other tech companies like Apple (and maybe to throw some of its own weight around). But Google also said that Motorola would be left as a separate business under its umbrella and would help it build new innovations (of some kind) into Android.

There’s been some concern voiced about how Google might treat its other Android partners now that it has an actual device maker under in its tent, but NPD doesn’t think that’ll be a problem and Google has said publically that things wouldn’t change with its partners. According to the press release, NPD believes Motorola might be able to make up some ground against its competitors in the prepaid market, where Android phones in general could start to muscle in. NPD says one in five phones sold in Q2 2011 was prepaid, and 22 percent of them were smartphones, up from just 8 percent during the same period last year.

Back when feature phones like Motorola’s Razr were king, the company dominated the prepaid market, so it makes sense that it might make a play for it again. Then again, who knows what plans Google might have for the company and how it wants to use it in the greater Android scheme? We’ll just have to wait and see.