I don't know how I missed this before, but only recently Boopsie for libraries reached my radar screen - it's a company that will create a mobile version of a library's website and catalog.
There are other options* out there, but Boopsie seems like a great and easy alternative to creating your own mobile website. And even better, they also mobile-ize the catalog, which I couldn't do (although apparently non-catalog services are more popular with mobile patrons).
Pricing seemed reasonable (for what you get) - a library near me is in the process of signing up, and reported the cost is in the few-thousand dollar range (or, it would be roughly $10,000 for our whole 36-library consortium to sign up). Lots of libraries are already using them - Sarah has a good write-up on San Jose's experience, and WorldCat and ALA also use their app.
I'm not trying to pitch Boopise, so much as I'm pitching the importance of libraries having a way to serve mobile patrons - using vendors like this* are an option for libraries who can't do it themselves.
*Library Anywhere from LibraryThing is another mobile website+catalog solution, and seems to be cheaper than Boopsie