I need to be able to dial in remotely to a client, I would like to know if anyone has used one of these programs and if you have opinions about them. Which one works better/worse?
I use GoToMeeting on a regular basis. Although the cost is pretty steep ($49.95/mo) - for me it well pays for itself because of the ability to help a client through setting something up, reviewing an issue or just managing something on their PC. It also gives the ability to hold a meeting for up to 15 people who can use their telephone or computer for audio. I love it and wouldn't give it up :-)
Here's another one to try. Joel and I have used it lots of time. It's Fog Creek Copilot. It's free on weekends, you can take a free 2-minute trial ride, get a day pass for only $5, or sign up for a low-cost option.