The easiest method is to download and install Samsung Kies. You can transfer all of your picture and music content to your computer while your phone is connected via usb cable. You'll need to download Kies 2.6, when the installation is finished, select 'Normal mode'.
The top left pane titled 'Connected devices' is where your contacts, music, photos, videos and podcasts are stored on your S2x. In the diagram below, if you select Music, Kies will search for all music stored on your phone.
You can select all of the music titles by clicking the circled checkbox and then right-click and select 'Save to PC'. You will be given the option to store it in a Music folder, or you can create or specify a new location, (e.g. Desktop) on your computer.