Visit dev.twitter.com, login with your twitter account and "Create an app".
Fill out the necessaries (as long as the formats are right, "http://www.espn.com" and whatever), agree the terms.
Now click the "Settings" tab and change "Application Type" to "Read and Write" and click "update this...." at the bottom of the page.
Then go back to the "Details" tab and click "Create my access token" at the bottom of the page.
Now copy the following 4 strings (they all look something like xadfdkj987hX0ou729ad934x) and string them together, separated by SPACE:
Consumer key
Consumer secret
Access token
Access token secret