Phazer,
You can do that several ways. First, you will have to be logged in to see the messages since your last visit. Once you are logged in, when you load the main index, you will see the number of new posts in each forum in blue, to the right of the total number of posts in that forum. Then click on the forum, and new posts have a red arrow inside of the 'post icon' folder.
Also, you can use the last day/last 2 days feature from the main index.
<font color=blue>>></font color=blue>Muhammad
<font color=blue>Administrator</font color=blue>