Good Afternoon Suzanne my name is Stason,
If you already have Quickbooks on one machine and you need to access it from a different location, not at the same site, then your best bet is www.gotomypc.com. Webex will not work because someone would need to be at the Quickbooks machine to click a box to allow you to connect remotely. GotomyPC installs an agent on your computer. When you log into their website you would be able to connect to your computer from anywhere as long as you had internet access at the location and the QB PC had internet access. GotoMyPC is not a free service unfortunately. There is another similar service call www.logmein.com. At one time it was free for personal use, but I am not sue if it is still free.
If you don't already have Quickbooks, they now offer an online version the you access with your web browser. My wife uses it and she likes it. It also lets you take credit card payments if you have the business version. They have an iphone app for taking payments and it automatically put the credit into your AR. That web address is http://quickbooks.intuit.com/online/
If you are using Windows and are trying to access it from another computer at the same site as the QB machine. You can turn on remote desktop on the QB machine and use the remote desktop client on the other machine to connect to the QB machine.
Do you have any further questions?