You need to make sure that the plug on the headphones has the 4 connection points. You should see three plastic rings on it separating these four connection points. But even then they might not work right.
Try searching this forum. A lot of people have had problems finding good ones to work with their pearl.
I just use the ones that came with mine. At first I was trying to get some Jabra C220s but ended up getting some counterfeit ones off eBay that didn't work right so I sent them back for a refund. Then I ordered some off of Amazon but they were through a 3rd company that advertised on Amazon. Long story short they were counterfeit too and didn't work right. So I just said screw it and started liking the ones that came with it.
Look at this thread: http://www.blackberryforums.com/gene...bra-c220s.html
If yours didn't come with headphones you can get the blackberry ones here: BlackberrySource.com - BlackBerry Stereo Headset