moving and renaming multiple files

Greetings,

I know i can use the mv command to move and rename one file. How can I do this with multiple files?

example
pic01.bmp to pic0001.bmp

how can i perform this function on an entire directory of sequential files and keep them in sequence?

Hints, suggestions are most welcome:)

cheers
roc

If you use the search you will find muliple thread discussing this.