Sorry, if this is in the wrong forum, feel free to move it

I am after an estimate of how much my website would be worth.

The website is http://www.zoobig.com and it comes with a sub site http://www.zoobig.com/free_myspace_layouts/

It earns $1000 -> $1 500 monthly via adsense and this month has 56992 unique visitors. Last month was 42327 unique visitors so it is reasonably consistant.

How much can I expect to sell it for?