Multi language support

[rvs2373]

Multi language support
I have installed Pligg for 3 websites, Now I have to make one of the pligg based sites in multiple languages. But I wanted that the user would access all its languages by a single username/password.
I wanted to use something like Cookie to control the multiple languages selection by the user.
I have read the Yankidank's suggestion on the forum link MultiPLIGG and I am going to use it to make it for a single login in multiple languages.
I am going to use 3 common tables (user, friends and messages) and all the other tables will be separate for each language.
I am going to use separate language.conf files for each language.
Would anyone suggest me where to define cookie for language and what other changes will be needed to use pligg in multi-lingual format.
I don't want to use babelfish or any other such facility as I have my own translator guys.

Thanks in advance...