What kind of downtime can I except for dental implants? How long before I can eat and will there be a lot of pain?

Depending on the case, how many placed and any adjunctive surgeries, one could say that there may be virtually zero downtime. Many have remarked that having fillings placed was more uncomfortable than dental implants.
If a single implant is placed in an area with adequate bone (no grafting needed, etc), then you may be able to have it done on a lunch break and no time off. It would be different if a sinus lift was necessary or block grafting, so it truly IS case dependent.
Most implant cases take 3-6 months to complete, but normal eating resumes during the process. Chewing may be altered initially, but should return to normal within a matter of days.

I can answer this from personal experience.  I have had a few teeth extracted and implants and bone graft performed.  The teeth fractured after years post root canal and crown.  I was back to work the next day with no problems.

The downtime that you will experience after having dental implants placed depends on several factors.  How many are you having placed? Where in the mouth are they?  Do you have good bone or will considerable bone grafting need to be done?  For those having one implant they can typically go to work the next day.  If your having 8-10 implants you will probably need to take off for a few days as you will be sore and on some pain medication.  You will be asked to eat soft foods only for a few days.  If there are multiple teeth that need to be extracted at the time of implant placement, the healing can take 1-2 weeks, before the soreness goes away.