This is Henbit, and it is really taking off with the warm weather we have been having. Control this with Weed-B-Gon and mix it strictly in accordance with the label. If you have the option , go with the highest rate allowable since it is a little harder to control than many other weeds that are present now.
This appears to be henbit. It is a common weed that appears during the winter. It is a member of the mint family. It should have a square stem, as do other members of the mint family. Normally, a pre-emergent done around mid-September should prevent germination. Once you see the weeds, you would use a post-emergent chemical to kill the weeds.