If you hover your mouse cursor over the link to your name in the facebook tool bar at the top of the page, you'll see the direct link to your facebook page in the status bar of your browser (providing you're not hiding the bar).

So, put your mouse cursor over your name link, right-click your mouse, and select the option to copy the URL. In Firefox, that would be "Copy Link Location".

Now paste it somewhere for safe keeping, so you don't have to repeat this exercise.

For example, your profile link looks like this:

http://www.facebook.com/profile.php?id=123456789012345&ref=name

The id= is your unique facebook ID. Yours will obviously be a different number.