How to install my app in adhoc release on multiple device with the same computer/itunes, when i try to do it, itunes sync the devices..so i clean them up ...
Apple has solved your problem with an Enterprise Utility called the "iPhone Configuration Utility" which you may freely download from their information webpage here: http://support.apple.com/downloads/iPhone_Configuration_Utility_2_0_for_Mac_OS_X
Once you install this and connect a device and close iTunes (which typically launches in response to the device connection) you can easily use its simple interface to manage your adhoc provision profiles, add the device and install or remove adhoc apps directly.
I used this app months ago to put the Crash Landing demo I'd built with the SDK directly on my wife's 2.1 iPhone 3G from my desktop dev Mac without messing up her own laptop Mac iTunes sync management of her apps, music, etc. FYI: I've not tried this since the June update to v2.0 of the Utility which accompanied the release of OS 3.0. edit: I couldn't resist testing this (yes, it still works)
The only downside I noticed to this method is that the iPhone/Touch user will have to later delete the app manually on their device, as their iTunes management won't list the app in the device applications tab to be unchecked.