Yes, I know this is six years old topic. However, decided that I will leave here my answer anyway. Maybe some of the readers will find it helpful. We are using/developing resource scheduling software at www.labandresourcescheduler.com. It's easy and intuitive. Maybe you would like to share your experience with this scheduler if you have any? I will be happy to discuss anytime.
We use this service at our school and it works great. It is way better than using Outlook/Exchange which we tried to use before and it provides us a way to schedule seats within our labs so that we can get better utilization. Instead of one teacher bringing a group of 10 students into the lab and blocking out the entire computer lab (30 computers), the system allows other teachers to schedule the seats not used.