An update manager is planned. More like an app store almost. This won't happen for awhile though. Probably CB 3.0. It's too far off right now to say specifically or provide much detail.
Core CB it self utilizes Joomlas own update usage though so updating CB will always be a breeze.
Our Plugin Management page does have a plugin version checker to let you know when an update is available, but that is dependent on our Package Builder. The issue here is we need to update Joomlapolis, which we're working on now, so we can update to CB 2.x and upgrade Package Builder. It then can be used to serve CB 2.x plugins, which will allow our plugin management page version checker to work again.
In the meantime Nick has put together and is maintaining the below compatibility page so you can see when updates are available.
www.joomlapolis.com/cb-20-addon-status