Windows XP allows you to rename multiple files in one stroke. Just select the files you want to rename in windows explorer and press F2. Rename the first file and press enter. Windows XP will change all the files with corresponding numbers in parenthesis.
For example if you have selected ocean.jpg, address.doc and accounts.xls and rename ocean.jpg to new then the subsequent files will be renamed to new (1) and new (2). The file extension will remain the same.
Hope you found this tip useful.