Unlike Pandora and Last.fm, Spotify has relied on actual clients to deliver music to its subscribers. Whether you're on the computer or a mobile device, Spotify has apps that will let you listen to your tunes, change stations, etc. However, this doesn't always work if you're using a computer that isn't yours, or you detest adding yet another app to your devices.
As an extra streaming option, Spotify is rolling out its Web player to user accounts. The Web player is located at http://play.spotify.com, but if you don't have access, you might still be able to get it without waiting. All you'll need to do is link your Facebook to your Spotify account.
To link your Facebook account
Step 1: Click on your username in the top right-hand corner of the Web site after logging in to Spotify, then choose Overview.
Step 2: On the right-hand side of the Web page, you should see information about manually linking your Facebook account. Click the link provided.
Step 3: Fill in your details (if necessary), then click the Add to Facebook button.
Now you just need to visit this link to use the Web player.
This means you can log in to the service via apps or the Web with your Facebook details. If so, just use this link to access the Spotify Web player.