I've done this.

When putting together a solution, I found this presentation useful.

I used Class::DBI to model `resources' within my web application wherein the actual translated text (where required) was located in a linked table/sub-class.

Use content-negotiation, as mentioned in the article you reference, backed up with an option to override. You'll want a look at HTTP::Negotiate now if you haven't seen it already. Maybe also one of the session modules for retaining user preferences.

You'd also be well advised to get your web-designer to consider how their pixel-perfect navigation is going to look in other languages ;)