Spotify’s opening up their entire music library to tablet and mobile devices today, with a twist. Free subscribers listening on tablets running Android or iOS will gain on-demand access to playlists, artists, and albums, mirroring the desktop experience. On smartphones, Spotify is adding shuffle play to their previous Spotify Radio offering, which lets free subscribers stream music from any artist or playlist. As always, free subscribers will have to listen to an occasional ad between songs. Check the table below for a quick comparison of Spotify’s current offerings:

Spotify’s online music streaming service is rolling out in 22 more countries today as well, making Spotify available in a total of 55 markets.

Lastly, Spotify is announcing that Led Zeppelin’s entire catalog of music will soon be exclusively available to stream, with the company doling out two albums every day until the Zeppelin’s entire discography is available. It’s equivalent to Apple gaining rights to sell The Beatles’ music on iTunes.

Be sure to visit the Spotify Blog for the latest news.