Automated Twitter Posting

We would like to offer our clients two ways to Tweet. One, by being able to directly enter their post into our Custom CMS, and have it post to their Twitter account. without having to leave their admin session, or their CMS page. Second, for them to be able to enter multiple posts into a database, which can then be scheduled to select posts in succession and post them once a day, or perhaps more. ie: if we had a database with 365 posts entered (kind of like a daily item) your script would take the very next item and post it to their Twitter account today, then grab the next one and post it tomorrow.