SMA DEPARTS ARPT WITHOUT CONTACTING NEW TWR.

Narrative

AFTER RENTING THE AIRPLANE; BUYING NEW MAPS AND COMPLETING THE PREFLT; ME; A COMMERCIAL/MULTI-ENG/INST AND CFI SEL AND MY FRIEND; A MEI/MEII; STARTED BOTH ENGS AND TAXIED TO RWY 17 AT F67 (GRAND PRAIRIE). AFTER COMPLETING THE PRE-TKOF CHKLIST; CHKING THE MAPS AND CLRING THE TFC AREA WE ANNOUNCED OUR INTENTIONS ON THE UNICOM FREQ OF 122.8. FINAL AND BASE WERE STILL CLR SO I TAXIED ONTO RWY 17 AND DEPARTED. WE MAINTAINED RWY HDG AND ANNOUNCED OUR DEP TO THE S. WHEN WE HAD REACHED ABOUT 1500 FT AGL WE RECEIVED A CALL ON 122.8 AND WERE TOLD THAT F67 NOW HAD A CTL TWR. I CONTACTED THE TWR ON 128.55 AND ASKED THEM WHAT TO DO ABOUT THE SIT. THE TWR ADVISED US THAT IT WAS ALRIGHT AND NOT TO WORRY ABOUT IT. HE SAID IT HAD BEEN HAPPENING A LOT. WE INFORMED HIM THAT THE NEW SECTIONAL WE HAD JUST BOUGHT HAD NOTHING ON IT INDICATING THAT F67 WAS NOW A CTLED FIELD. I ALSO CHKED DUATS AND DID NOT FIND ANY NOTAMS ON THE NEWLY CTLED FIELD. THERE ALSO WERE NOT ANY MARKINGS ON THE FIELD; (IE; CONTACT TWR FREQ SIGNS AT THE END OF THE RWY) AS I HAVE SEEN AT OTHER CTLED ARPTS.