I can't connect wifi tether network with tablet I used wifi tether application to share internet connection in rooted xperia x8 android 2.1 version. It is work for my laptop.
I can connect this network correctly with my laptop. But I can not connect this network with another android phone or tablet.
Because this network does not appear in another android phone or tablet. What setting should I change?
Most likely, your X8 is broadcasting the wireless network in ad-hoc mode rather than infrastructure (AP) mode. Android does not natively support ad-hoc wireless connections, which is why your tablet cannot see or connect to the hotspot.

Your options depend largely on the state of your devices. If your phone is rooted then you can try a custom ROM or kernel that is built with support for infrastructure mode. XDA's X8 sub-forum would be a good place to start looking for a ROM/kernel that suits your needs. Custom ROMs may list infrastructure or wifi tethering support in their features, though you may have to skim the ROM's thread as a whole to find out.

If your tablet is rooted then you could try to find a wireless module that has been built to support ad-hoc mode. There are modifications for many mainstream tablets that will enable this functionality, usually consisting of a patched version of the wpa_supplicant binary that would need to be installed on your device.

If neither device is rooted then there is probably not much you can do. You may want to look into other alternatives, such as perhaps Bluetooth tethering.