For twitter you can have it look for updates as often as you want. It is very easy to do.
Go to http://www.twitterfeed.com. Set up an account by entering your email and a password. Then all you have to do is point enter your twitter name and password and let it find the link. Once you do that you will type in the feed url which would be http://username.wordpress.com/feed/ (type your blog address where username is). Check to see if it connects. You can then go to advanced options to tell it how often to check wordpress.
It will then pull your blogs by name and description with a small link.
Let me know if you have any questions!
Cherry Designs, Inc.