I was actually looking for the same thing and came across August SmartLock, which seems okay. It is a DIY installation smart lock. Do a quick search on Google to find who the sellers are. Prices vary depending on the model (there's a pro version and a regular version -- I was told the only difference is battery consumption). If you want to be able to control this remotely, you will need the WiFi bridge. Otherwise, it can be controlled by bluetooth. It's a bit expensive and I really wanted to install that one because there's no need to change the outer appearance of the locks (many condos don't allow changing the lockset -- ie Avida and SMDC). However, on the day I was suppose to buy it I found out that my lock set is a double turn, so it just won't work. There are many options for condos that allow changing the outer appearance of the lockset, Yale is a good one.
I've seen some people use lockboxes but I have no idea how they do it. Hope someone else can contribute to this thread!
