The single best way to consult is to be there in person to speak to the client face-to-face. However, in fields such as you're interested in Anthony (web design) your clients can often come from anywhere in the world.

Personally I would steer clear from using IM programs (AIM, MSN, et al.) but there is nothing wrong at all with speaking to the person over the phone (or computer-based telephony). Phone conversations take place in real time, and you're talking to a real person which is something IM programs tend to abstract.

Do you want to spend 4 hours travelling to talk to a client for an hour, or just get a call from them? (Depends if they'd pay for the private jet and hotel )