anyone familiar with how the block explorer works?

http://blockexp.com:3004

its not showing my correct balance, and does show all my transactions, but one of the transactions shows the amount split and going to another unknown address and on my wallet it has this address labeled as "change". my wallet shows the correct amount, but can someone help me figure this out? im using the block explorer to keep track of my balance. you can pm me so we dont fill up this thread.

thanks!