Hi Becky,
All brokers are able to provide the ability to trade on-line. Most brokers will allow you to test drive their trading platforms with a demo account for a short period of time. The objective there is to test the platform for look and feel. Once you have checked out the on-line trading platform for usability, the difference in brokerages may be in the support provided by the broker in the event that the on-line trading platform is not accessible for any reason (the platform itself, your ISP, your computer, or any other reason). My suggestion would be to start by contacting the brokers recommended by Tom in the "Broker Dudes" section of the Support and Resistance site. Just click on the link below.