How to find Free disk space available from SQL query

Hi all,
I have to find free disc space in a drive from SQL Query and i am using MSSQL200. Does any body know the command for the same.

Also if i want to find hard disk space of a different machine on network, it is possible to get the data??

Also can i get the CPU/Memory usage data of our machine by some SQL/C++ commands??

Please let me know if u know any of the answer...

thanks
Alokxp_fixeddrives for free disk space...looking for others...