By this trick you can easily save chat of your friend who is 'off the record' with you.
Follows these steps:
1. You need a Pidgin Messenger which you can download fromPidgin official website: http://pidgin.im
2. After installing you have to configure your account with your gmail id as shown in figure.
3. Login in to Pidgin client.
4. Select tool menu->Prefrence.
5. A dialog box is there like in Image below. Select it logging tab. select the chat log format either Html/Plain. and
check all checkboxes there. then cliek ok.
All of your chat now logged in to system either its is on 'off the record' or not.
6. In Windows it saved in Application Data folder and in linux your can found in home directory.
For Example if you logged in windows With user1 account
then you can find your chat in folder C:\Documents and Settings\user1\Application Data\.purple
In Linux you can find .purpule folder in user's home directory.