From the Google Geo Developers Blog...

Announcing Google Maps API v3

This is good news for iPhone users (and to a lesser extent Android users) because of these parts of that announcement...

[...]The primary motivation behind this new version was speed, especially for rendering maps on mobile browsers.[...]

[...]Chrome and iPhone Safari mobile added to our supported browsers. Your mashups will also work on Android-based phones with the recent update, but you may notice some issues, like the "View/Save Image" dialog showing unexpectedly. We're working with the Android team to fix this and improve the end user's experience in interacting with the map. We could've waited until it's perfect, but we really wanted to get an early release in your hands and start getting feedback while we fix up a few remaining issues.[...]

So, iPhone and Android phone users should see some interesting Google Maps mashups as soon as mobile web developers start using the new API.