[ms4w-users] geographic projection converted to Mercator?

[Tib Kat]

Hi
I'm a complete novice using MapServer still gettting familiar with the 
structure and what can and cannot be done.
My client has Geographic Projection image and I'll need to have them 
served as Mercator Projection.

Can MapServer do this sort of transformation ?
is it more efficient to directly use Mercator removing the CPU Load of 
converting one format to the other.
 is there a caching device so this is done only once ?
If my original image is 10000x10000 and I need to be served 256x256 
tiles according to the viewing section is this also possible?

Thanks for the help
Regards
Tibor