Php Function, to extract link from short text

[Seco]

I am looking fo a function, to extract the mp3 source of this snippet of code:\[code\]http://www.xyz.com/previews/speed_racer_preview.mp3 1930510 audio/mpeg\[/code\]i only need that part:\[code\]http://www.xyz.com/previews/speed_racer_preview.mp3\[/code\]This part always has the same structure, only the source changes.