Suddenly, the subscription-music space is getting pretty crowded. Omnifone, the UK B2B vendor whose MusicStation app has been live on several carriers’ handsets for about three years now, says it’s won a deal in which HP will pre-bundle a desktop version on its PCs in 10 European countries.

The app gives new HP owners a two-week trial of unlimited music downloads, after which a monthly subscription costs £8.99 or, outside the UK, €9.99. Tracks come in DRM’ed WMA format, and will remain playable only while users have an active subscription, which can be canceled at any time. The sub will also give 10 unprotected MP3s free each month.

Comparisons with a certain Apple (NSDQ: AAPL) and a certain Spotify are inevitable. Asked about the latter, Omnifone PR Tim Hadley said: “This service is available in 10 territories across Europe (referring to Spotify’s six) - it’s got a wider reach immediately. For the same pricepoint, or less in the UK (Spotify is £9.99) - unlimited access to identical-sized catalogue (6.5 million tracks), plus you get to keep 10 favourite tracks. You can also unplug or disconnect - it’s not dependent on being online.”  It’s also “an alternative means of consumption to iTunes’ a la carte model”, Hadley said.

It’s a good deal for Omnifone - the trial on 16 models of HP laptop and desktop machine could mean a bump for its subscriber count, which the company declined to quantify for us. And HP, which has been prebundling RealNetworks’ Rhapsody on U.S. machines for some time, gets a European alternative. But, unlike mobile-centric MusicStation’s sole other desktop deal - with Three in Hong Kong - this is a PC-only offering; tracks cannot be parallel-downloaded to mobile phones.

Neither Apple, nor Spotify, nor MusicStation are alone in this space. Mog.com is showing growing ambition in the unlimited-music space, Rhapsody has been doing it for years, Rdio is due to launch in the next few months, We7 is launching a subscription service on February 1. With licensing frameworks in place, labels are now keen to get legal music relationships with as many good licensed services as possible - meaning a digital opportunity for such services.

Apple may be tempted to augment its per-track download store with a monthly unlimited-access package as the number of participants in this race grows - right now, it’s proving late to that game; but ultimately, it may yet hold its music lead.