Clarification needed in Exchange Server!

Hi all,
I am a beginner in MSExchange server administration. I deleted few of the mail boxes and cleanes few mail boxes. But, the free space size of the harddisk remains the same. What are all the possible areas should i check to make sure that i’ve saved some space?

The same thing happens in VSS also. If you could tell me a solution for this also, it would be great.

Thanks in advance.

My mail id is hicheery@yahoo.com

Magesh.