OptionsHouse is a new broker (January 07) that offers aggressive pricing for option traders. The cost for options trades are a flat $9.95. So for one contract you pay $9.95, 10 contracts $9.95, and fifty option contracts $9.95.
While OptionsHouse is a new brokerage it was given four stars by Barron's in the March 2007 stock broker review and rated as one of the best brokers for options traders.
For those who trade high volume contracts it may be worth a look.