How to "mass" renaming files

[Josef Lowder]

Can anyone provide a simple shell script command to 
change the file names of all the files in a given directory? 
	from pict0001.jpg to just 01.jpg 
	from pict0002.jpg to just 02.jpg etc. etc. 
with the numbers running to a few hundred pix, all with 
the same "pict00..." first part of the filename. 

I looked on the 'net to find a shell script to "mass" rename the files 
in any given directory and found the example below to rename the 
suffix from php3 to just php, but I couldn't figure out how to modify 
that to change the filename itself. 

 ls -d *.php3 | sed 's/\(.*\).php3$/mv "&" "\1.php"/' | sh 

I also found a *nix utility on my system named 'rename' but I 
couldn't get it to work.  Below is an excerpt from the 'man' page 
for 'rename' ... but what in the world is 'foo'?? 

MAN PAGE excerpt: 
rename will rename the specified files by replacing 
the first occurrence of from in their name by to. 
For example, given the files foo1, ..., foo9, foo10, ..., foo278, the 
commands

rename foo foo0 foo? 
 rename foo foo0 foo?? 

will turn them into foo001, ..., foo009, foo010, ..., foo278.
And
rename .htm .html *.htm		will fix the extension of your html files.