Tip 4 - Analyze your broadband regularly.
Your broadband can make or break the quality of a voip call. Even if you're paying through the nose for "really fast" service, that doesn't mean you're getting it reliably enough for high quality calls. Sometimes, even if your speed is fast, you might be experiencing lots of tiny little connection drops, or your packets might be getting hung up, or even network congestion can muck things up.
How about some tips for using VoIP over your Wi-Fi handhelds? Does anyone have tips for setting up wireless VoIP? Please, please share them with us.