admin on "eMember - Protect forums to certain level"

You do this using WordPress user role capabilities. You can hook each eMember's membership level to a particular WP User role so when a user signs up the user will have that WordPress role applied. Now, other WordPress plugin's that uses WordPress user role will work based on the user's role. More details here:
http://www.tipsandtricks-hq.com/wordpress-membership/using-emember-with-another-plugin-that-uses-the-wordpress-user-roles-350