HootSuite lets you manage your entire Twitter experience from one easy-to-use interface.
Creating an account is easy. Enter your Twitter username and password, and add a profile for each Twitter account you wish to manage. Got more than one tweeter per profile? Add multiple editors.
Then get going! Post live or pre-schedule tweets. Check stats and analytics right from the dashboard. Search Twitter for keyword information. Reply @ and Direct Message the folks in your conversation. Do all this and more from one fantastic interface.
One cool feature of HootSuite is it provieds a widget of your tweets (or others!) to put in your blog or website.