1)Tethering (Letting laptop to use the 3G internet)
yes, there is an app included, but t is in chineese. though some people say that any tethering app will work. edit: ( can comfirm that the free tethering app also works)
2)CAn i convert all the text/apps to english?
No, you can convert most of the OS to english (one or two things are not) but none of the original apps.
3)Is there any english apps/program for this phone?
It is possible to use any google app with the LeOS 2.0 or better (Im sure there are exceptions)
4)How can icheck my android version and whats the current latest version
If you are refering to the android verion of LePhone, then its in the info app, for other phones ask in the corect forum
If you want to see screenshots of diffrent versions with download links see my site: http://kbob.dyndns.org/lephone