Gmail is based on search, not sort. Google mail features the same powerful search technology used on the Web to perform accurate keyword searches of all of your email and attachments. Search by keyword, label, date range, or a host of other options.
From the search box you can also use the following search operators and shortcuts:
For the latest shortcuts visit: http://mail.google.com/support/bin/answer.py?hl=en&answer=7190