Authlogic will work fine in Rails 2.3.8. If you are looking to do authorization, I'd recommend you check out Can Can (a great gem written by Ryan Bates). It will integrate without too much trouble.
I need to set up logins for my small application. I notice a number of plugins are available. Authlogic seems the most popular. Is it suitable to use with rails 2.3.8? Can I use authlogic to authorise users stored in 2 models/tables? Any thoughts about the best way to do this please?