On the last couple of projects I’ve been working on the clients both wanted an area of their website PRIVATE or for MEMBERS ONLY. I found a different solution for each of them with two nice plugins for WordPress that you may find helpful too.
One of the simple ones I used was Membership Lite – http://wordpress.org/extend/plugins/membership/
This one has two levels that you can set up for visitors so for this particular client we set up a regular site visitor that may want to comment on articles and we set up an employee level membership that will be able to access some things others won’t be able to see (even if they’re logged in). You can also set up subscriptions (you get two with the lite version) that expire and take payments for your memberships. It also comes out of the box with a free subscription and a paypal payment subscription so you can charge for memberships. This is a nice and simple plugin with the ability to purchase a pro version with more membership levels, subscriptions and lots more features.
A little more complicated but comes with some more choices was S2Membership – http://wordpress.org/extend/plugins/s2member/
This one has five levels of membership possible with level zero being a free membership and levels 1 – 4, this one can be set up for use with paypal and even recurring payments. This one has a LOT of potential for some serious API programming and customization. I merely used it for a visitor vs member being able to access certain areas of the website, but there’s more potential here. It’s pretty slick. I chose this one in particular for my project as they needed a custom form for a person who wanted membership to fill out.
Each of these plugins gives you the ability to protect pages, posts, categories, tags and even part of pages/posts with shortcode. I really liked both of them and will probably be using them in the future more.