132346 Need user/password script

Hi, am buildding a website and need to have a system to give users a User ID and a Password so they can access "Some or All" areas of the website. The system should be capable to generate a temporary User ID and Password for a visitor to used for a limited period of time and then expire. I want to have total control of these "user Ids and passwords" from a back panel and keep records of visitors that have access the website. I'm still not sure if I'm going to have the login boxes in the home page or maybe have an flash intro and have people login right after the flash intro is done , not sure yet, but so far thats what I need to have people visit website. If someone can help, post a message, if you want to bid on this project, please post a message first, I do not consider bids with no message, please also send links to projects you have done on this categorie, thanks!