P&O Ferries, run a sailing every 30 minutes at peak times, crossing time approximately 1hr 15mins.
http://www.poferries.com/tourist/bookJourney.html

Sea France, 15 crossings daily, crossing time of 1hr 30mins
http://www.seafrance.com/seafrance/opencms/uk/en/passenger

Brittany Ferries offer a number of crossings into France, some of these crossing are on the new high speed ferry and can cut your travelling time down by half, though a little bit more expensive they offer a quick and convenient means of getting to your destination.

• Poole to Cherbourg
• Portsmouth to Caen
• Portsmouth to Cherbourg
• Portsmouth to St Malo
  Further details can be found here: http://www.brittanyferries.co.uk/

Speed Ferries If you're looking for a quick way to get to France, then look no further than Speed Ferries, from March 2007 they will be offering up to 8 crossing a day a price that will be hard to beat, for further details go to:
http://www.speedferries.com/speed_4.0.php

LD Lines Ferries.  This ferry service is relatively new to the cross channel hopper, offering a very comfortable up to date ferry with all the amenities you could wish for, all at a reasonable price, if you are looking to shorten your drive time down in France, then this service is worth considering.
Sailing from Portsmouth to Le Harve daily.
Departs Portsmouth at 23.00 and arrives at Le Harve 07.30
Departs Le Harve at 17.00 and arrives at Portsmouth at 21.30
For further details go to: http://www.ldlines.co.uk