According to the latest data released by The NPD Group, iTunes now represents a quarter—25%—of all retail music sales in the United States, more than ten percent more than its closest competitor. Based on all music sold in the first half of 2009, iTunes sold 25 percent of it, up from 21 percent in 2008 and 14 percent in 2007.

iTunes 9 will feature Blu-ray disc support, as well as a better way to handle iPhone and iPod touch applications, according to a new report. Citing a “pretty reliable source,” Boy Genius Report writes that Blu-ray support will be coming in the next version of iTunes, which is curious considering that Apple currently doesn’t sell any of its own computers with Blu-ray drives installed.

Apple has officially launched the iTunes Music Store in Mexico (Translated Link), letting customers there purchase songs and music videos alongside the previously available iPhone applications from the App Store. According to a report from Mundo Mac, songs are priced at 12 pesos—or roughly $0.91—each, while music videos sell for double that amount.

Apple has added a new Travel Guide section to the iTunes Store.

Apple is working with the four major music labels—EMI, Sony, Warner Bros., and UMG—on a new type of album bundle aimed at boosting sales of complete albums on the iTunes Store. The Financial Times reports that the project, code-named “Cocktail,” will include interactive liner notes, videos, lyrics, and other interactive content with albums, expanding on the current bundles already available.

Palm has released webOS 1.1, bringing with it a number of new features and improvements for the company’s Pre smartphone. Most notable for iLounge readers, however, is the re-enabling of what Palm calls “media sync,” which allows Pre users to connect their devices to iTunes and sync their media as if it was an iPod.

Apple has released iTunes 8.2.1, its latest update to its digital media management software.

Harkening back to the days of the vinyl 45 rpm record, the iTunes Store has launched a new section of the store for “D45s.” As with vinyl 45s, these new digital packs contain two songs, traditionally made up of a single and B-side.

A group of U.K.-based DJs has been arrested for using iTunes and stolen or fraudulent credit cards to boost their chart rankings and steal royalty fees. Metro.co.uk reports that the nine musicians are accused of providing 19 songs to US-based distributor Tunecore, which uploaded the songs to iTunes and Amazon for sale. Once online, the DJs then opened accounts with stolen or cloned U.S. and U.K.

Developer “DVD” Jon Johansen has posted a brief article explaining the Palm Pre’s unsupported ”Media Sync” feature, which allows it to appear and sync as an iPod through iTunes. According to information provided to Johansen, the Pre’s Mass Storage interface identifies itself as an iPod, enabling it to trick iTunes and sync.