The most common way to get to Coban from Guatemala City is using the Monja Blanca bus service from the capital, approximately four hours. There are also competitors, as well as more expensive shuttles. A ticket to Coban on the Monja Blanca costs about 60 Quetzales per person (as of 2009).
From the Western Highlands, regular microbuses run from Quiche to Sacapulas to Uspantin to Coban (you will probably have to change buses in each town). The road between Uspantin and Coban is only paved about half way, and has some rough stretches. Travel time (in 2010), including time spent waiting for buses, is about 6 hours from Quiche to Coban and 2.5 hours from Uspantin to Coban.
Coban is a relatively walkable city in terms of size (sidewalk conditions are horrible, however, and you should always assume that cars will take the right of way). For local destinations around Coban, there are buses that leave in front of Plaza Magdalena. You can take a taxi almost anywhere around town for between Q15 and Q20. Always get in the taxis that are marked with a Taxi number on the door, the unmarked ones are not licensed to work as a taxi.
the Main Cathedral at the town Center. Semuc Champey about two hours from Coban. There are private tours you can hire to get there. Check with Hostal d'Acuna or Hostal de Dona Victoria.
You don't have to book tours or walk around with your nose buried in your LP guidebook to figure all this out. If you want to go to Champey, hop on a colectivo across from Plaza Magdalena (a big yellow shopping mall - everyone knows it, just ask) and go to Lanquin; get off there, hit up the dudes at El Zapote immediately to your right when you get off for a free ride down to Las Marias hostel, and pay 15Q for a mattress and 15Q for a tour. Simple as that.
"De La Abuela" Hotel and restaurant serves traditional dishes and fresh seafood, but their specialty is the meatiest barbecue ribs in Guatemala. They have outdoor eating areas upstairs and downstairs surrounded by nature, the atmosphere and service are very friendly.
Tourists tend to spend only a night or two in Coban. The most popular place to stay is Casa d'Acuna, which is a relatively inexpensive and reliable hostel. There are a number of other small hotels around the main plaza, though, most of which are comparable in price.
The newest hotel and restaurant De La Abuela sits on a hill on the main road as you enter Coban. Their bedrooms and bungalows can accommodate families and large groups.
La Paz Hotel is very pretty, relatively quiet, has a friendly staff and as much security as one could desire; single with private bath is 45Q. Next to La Paz are the B&B Rooms, a dorm-type affair run by a Mexican-American; low prices, cool ambience. Stay away from the Hotel Familiar, which is filthy (25Q), and especially the Tourist Information Office, which is actually a hotel and restaurant which sells information you don't really need. There are other hotels away from the center but they're hardly worth hunting down for the prices.
Los Faroles Hotel  is very beautiful. The service is personalized and friendly, as they strive to make people feel "en Su Casa" ;).
Most buses and microbuses use the northern bus terminal, located about 1.5 km from the city centre, rather than the Monja Blanca station. Travel agencies and Casa d'Acuna will book shuttles.