Julie, it seems as if online service scheduling with a robust admin has taken a back seat over the last couple years. However I believe we are on the verge of seeing another increase in the demand for such services. For years I swore up and down that @utoRevenue (acquired by Dominion) was one of the best. They had a one of the simplest consumer facing (mobile too) service scheduler. The admin was decent but the automated retention touch points (email, voice and print) all worked together very well. They provided some nice reporting as well.
I can no longer speak with authority on behalf of @autorevenue/Dominion product since it's been too long. Taking a quick look at their website, I wasn't able to find any information on their service scheduler and retention marketing.
I've worked with a few dealers using Autoloop and I've like what I see. They provide an online scheduler with retention feature. On top of that, they offer their "SmartLane" product that provides your service lane process into the efficiency of of an iPad: iPad Reception, Inspection, Photo Capture, Checklists, Customer Updates and even signature capturing on the iPad. I'm not selling nor do I endorse AutoLoop but from what I have seen, it offers many of the features the OEM's are looking for dealers to adopt.
Elead's autopilot may be another service worth checking out, especially if you're already an eLeadCRM customer.
There are a several services to choose from but most of them don't provide a seamless online service scheduler with a solid retention feature that ALSO offers an Inspection / Upsell component. But if you're not looking for the Inspection / Menu upsell component, then you have more options to choose from.
Here are a few more companies that you may want to reseach:
Dealer-FX
AutoAppoint by CIMA Systems
Service Drive Suite by MOC1 Solutions
TimeHighway
X-Time