If you click on a user's name on his post, you'll get a little drop-down menu. One of the choices there is "Find other posts by this user". Choosing that after clicking your own name would bring you a list of your posts.
You can also use the SEARCH button to look for your posts. Click on SEARCH, then choose ADVANCED SEARCH. You can input a user name, plus a number of other options.
In addition, you might want to subscribe to certain threads so you'll easily see when there are posts added to them. To subscribe to a thread, look for the THREAD TOOLS option at the top of the first post on a page, then select SUBSCRIBE TO THIS THREAD. You can then then see any of your subscribed threads that have new posts quickly anytime you click on User CP!