corporateboy wrote:...All suggestions welcome.
Well, cos I am always ready to share my two cents, I suggest you check out this article: http://www.sitepoint.com/article/great-client-login-system
It helps you to plan your site for logging in your clients. Then, you could check out all the great tutorials available and learn to code this yourself using PHP (sessions, cookies, header-redirects, etc...) and mySQL database (store users info, search to see if login info matches, allow users to update email info, etc...)
I was able to do this for my Brother-in-laws site myself in a short while after taking online tutorials, doing my own tests/examples, and posting questions here. THis is a great community of people who will help you if you show a little initiative and try to write the code yourself. If you get stuck, there will be a lot of support and guidance from real gurus here. (I am still a newbie...)
Some great tutorials are available here
And Codewalkers has a good tutorial on a basic authorization system here (the concepts are good, but I recommend reading a few different articles from a few different sites to get a better perspective and ideas how to write the most secure code. People here will also help you develop good strategies for secure site)
Good luck. Let me know if this is helpful, or if you would like any more info on tutorials....