Tour packages are not common in Isan, but travel agents and guesthouses in most major towns may be able to offer services. The harder to get to Khmer ruins near Surin and Si Saket would be the best places to make use of a tour or rental car. Recommended operators are listed in the appropriate region. English-speaking guides are few in number, so be sure to specify that you require one. Otherwise, you may find yourself paying for a driver and pointer.
The Tourism Authority of Thailand (TAT www.tourismthailand.org) has branches in most cities and is a good source of information. Most branches are open daily from; typical hours are 8:30 to 4:30.
TAT (Korat) (2102-2104 Mittraphap Rd. 044/213666).
TAT (Surin) (Th. Thessaban 1 and Sirirat Rd., Krungsurinnork. 044/514447 or 089/201-7985).
TAT (Ubon Ratchathani) (264/1 Khuan Thani Rd. 045/243770).
TAT (Udon Thani) (16/5 Mukmontri Rd. 042/325406).
TAT (Khon Kaen) (15/5 Prachasamosorn Rd. 043/244498 or 043/244499).
TAT (Loei) (Charoenrat Rd. 042/812812).
TAT (Nong Khai) (Thai-Laos Friendship Bridge Rd. 042/467844).