Hi,
How are you? Both calcium and beta blockers are antihypertensive medications. The difference is the type of channels they block in a cell. Beta-blockers reduce nerve impulses to the heart and blood vessels leading to slower heart beat slower and lesser force lowering the blood pressure. Calcium channel blockers (CCBs), on the other hand, keep calcium from entering the muscle cells of the heart and blood vessels. This causes the blood vessels to relax and the pressure goes down. The links above are very helpful. Take care and regards.
Here are some websites that may be useful to you the first one is about beta blockers and the second one is for calcium channel blockers
http://www.medicinenet.com/beta_blockers/article.htm
http://en.wikipedia.org/wiki/Calcium_channel_blocker
Hope this helps