Central Government has issued notification No.29/2008-Service Tax, dated 26.06.2008 to exempt fully from levy of service tax on supply of transport vehicles (goods carriage) to a goods transport agency (GTA) to be used for transport of goods by road [section 65(105)(zzzzj) of the Finance Act, 1994].
Services provided by a GTA in relation to transportation of goods is leviable to service tax under GTA service [section 65(105)(zzp)]. Service tax for the GTA service provided is payable only on 25% of the amount charged for providing the GTA service and the balance amount is exempt from levy of service tax.
You can avail the Cenvat Credit on Inbound Transportation undoubtedly. But for outward transportation, please refer the ST Circular No 97/8/2007