Is this normal? (soft click coming from the hard drive)

[gakuran hitori]

On my new 2011 MBP there's a soft click coming from the hard drive every few seconds. It's very faint and the fan speeds up slightly when it does this. I've recorded the sound with a zoom h4:

http://www.mediafire.com/?tabg8v9x7dg3pbu

Is it something I should worry about? I didn't notice it start doing this until two days ago.

 

[Transeau]

It's nothing to worry about. It's just the hard drive head parking to protect it / safe power.