I used SwitchTheme module to switch theme for mobile terminals up to now. But I looked for another module, because Browscap, which is co-working with SwitchTheme to detect mobile terminals, doesn't work well recently.
I found Mobile Tools module. Now I use this module to switch theme when accessed from mobile terminals such as Android.
The document concerning Mobile Tools is here.
After install as the same way of other modules, basically it works soon well.
Mobile Tools settings
Select a switching method to the theme for mobile from two methods. One is redirecting to URL for mobile, and another is switching themes with same URL.
Here, because I want to use the same URL, Mobile URL and Desktop URL are made the same.
Mobile Tools block message options are settings of blocks to display desktop theme screen and mobile theme screen separately. Here, on the desktop theme screen, display a link to mobile theme, and on a mobile theme screen, display a link to desktop theme.
The method of changing the theme is specified. Here, set to "Switch theme for a mobile device". And set a default theme name and theme names for each device group (iPhone, iPod, iPad, Android, ...). I use nokia_mobile for all type of mobile device.
Mobile Tools module generates Mobile Tools message block. I set this block at a footer region. On mobile theme, a link of "to PC View" to switch desktop theme appears at the footer, and on desktop theme, a link of "to Mobile View" appears at the footer.
Tweak mobile theme
I adjusted "nokia_mobile" theme a little with checking by my android phone. I also add Google AdSense ad for mobile.