when is the best time to plant tulips from bulbs...i live in north texas?

Ideally, you should plant 6 weeks before the first frost. The ground should be around 60 degrees when you plant. Here is some good info all about bulbs:

http://www.bulbsociety.org/About_Bulbs/BULB_BASICS...

Don't know what your winter temps are but usually spring blooming bulbs get planted in the fall, then they come up in place and bloom in the spring. When buying bulbs make sure that they are not squishy. Worth a trip to the local garden center and research what they have.

Do your winters get cold enough for the tulips?

now September but they will just last one season not cold enough to bloom next unless you dig up and refrigerate but there is no guarantee this will work