Here are most of the important apps for the Android operating system. Sensei's Library [1] contains more details about these and other apps.
If you're a beginner please have a look at our Top Picks for Beginners page [2] which contains our initial recommendations for you.
These are in English and all allow users to interact with other users, players and games on the servers they support. They are all free and require you to get an account before you can use them.
Most of these also allow for game recording and editing
These are mainly for problem review and solving:
The Gobandroid, WegoIgo and anDGS information is abstracted from the American Go E-Journal review in July 25, 2012 [18].
Links:
[1] http://senseis.xmp.net/?Android
[2] http://www.britgo.org/gopcres/tips
[3] https://play.google.com/store/apps/details?id=fm.wars.goquest
[4] https://play.google.com/store/apps/details?id=be.gentgo.tetsuki&feature=also_installed#?t=W251bGwsMSwxLDEwNCwiYmUuZ2VudGdvLnRldHN1a2kiXQ..
[5] https://play.google.com/store/apps/details?id=com.gokgs.client.android&feature=also_installed#?t=W251bGwsMSwxLDEwNCwiY29tLmdva2dzLmNsaWVudC5hbmRyb2lkIl0.
[6] https://play.google.com/store/apps/details?id=couk.doridori.goigoFull&feature=related_apps#?t=W251bGwsMSwxLDEwOSwiY291ay5kb3JpZG9yaS5nb2lnb0Z1bGwiXQ..
[7] https://play.google.com/store/apps/details?id=com.hg.anDGS&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5oZy5hbkRHUyJd
[8] https://play.google.com/store/apps/details?id=de.agrothe.go&feature=related_apps#?t=W251bGwsMSwxLDEwOSwiZGUuYWdyb3RoZS5nbyJd
[9] https://play.google.com/store/apps/details?id=org.ligi.gobandroidhd.ai.gnugo
[10] https://play.google.com/store/apps/details?id=org.ligi.gobandroid.ai.gnugo&feature=nav_other#?t=W251bGwsMSwyLDYsIm9yZy5saWdpLmdvYmFuZHJvaWQuYWkuZ251Z28iXQ..
[11] https://play.google.com/store/apps/details?id=us.danlib.igo.lite&feature=search_result#?t=W251bGwsMSwxLDEsInVzLmRhbmxpYi5pZ28ubGl0ZSJd
[12] https://play.google.com/store/apps/details?id=lrstudios.games.ego&hl=en
[13] https://play.google.com/store/apps/details?id=jp.co.unbalance.android.igoen&feature=also_installed#?t=W251bGwsMSwxLDEwNCwianAuY28udW5iYWxhbmNlLmFuZHJvaWQuaWdvZW4iXQ..
[14] https://play.google.com/store/apps/details?id=uk.co.aifactory.go&feature=related_apps#?t=W251bGwsMSwyLDEwOSwidWsuY28uYWlmYWN0b3J5LmdvIl0.
[15] https://play.google.com/store/apps/details?id=com.ssj.igo&feature=related_apps#?t=W251bGwsMSwxLDEwOSwiY29tLnNzai5pZ28iXQ..
[16] https://play.google.com/store/apps/details?id=com.gogrinder&feature=also_installed
[17] https://play.google.com/store/apps/details?id=com.timk.goedit&feature=more_from_developer#?t=W251bGwsMSwxLDEwMiwiY29tLnRpbWsuZ29lZGl0Il0.
[18] http://www.usgo.org/news/2012/07/android-go-programs/