Talk with friends or neighbors who may have used pest control services and request their input or referral.
Contact the Better Business Bureau to be sure you will be dealing with a reputable company. The BBB website (see Resources) allows you to search for local businesses by type within a 500 mile range of your zip code. The BBB rates members as well as non-members and lists any reported complaints.
Call your chosen pest control business and request a home visit and an estimate for extermination. Some of the larger companies such as Orkin have an online form (see Resources) that allows you to request an estimate even when their offices are closed.
Schedule a time when you will be available to allow a thorough home inspection. Daylight hours are best so that the pest control representative can clearly see all entry ways and exits that your visitors are using.