I have a combination of A61 tip and another iGo unit. It charges my 3G iphone fine. However, at the Radio Shack where I bought the tip and unit, they told me that A61 was not compatible with 3G iphone and I needed to buy a new tip A133. Honestly, I don't know whether this is a scam to sell a new tip, or there is indeed some sort of incompatibility.

I am also looking for iPhone 3G adaptor. But the iGo website (www.igo.com) does not list this product at all. If I search an adaptor for iPhone 3G then they display model A133 and not A61. I think this is not supported.