... Mobile OPAC, and put together a implementation plan ...
Some thoughts from a non-Koha-specific perspective. As background, I spent some time working on a mobile Tomcat skin for my Voyager ILS, but ended up scrapping that as we were close to deploying Summon, which has a mobile version. We're currently working on something to fill in the gaps between them - user account info and hold etc requests - with pages that will serve both desktop and mobile.
CSS-based, or a new template?
I would say both. :-) There are some advantages to having separate mobile pages, but the general move seems to be towards responsive web design [1], i.e. adapting the layout for the user. Particularly for something like an OPAC I think that it's advantageous to have a URL that works everywhere, not just on a desktop OR a mobile. It's not necessarily as straightforward as picking CSS templates using media queries. There are a couple of reasons why it's probably a good idea to create a new template for this, rather than bolting additions onto an existing one. One is that it's important to limit what's downloaded on mobiles - for performance and bandwidth charges. It's easy to tell the browser to resize a large image, or to just hide extra stuff that's not displayed (but still downloaded), but it would be much better for the users to take the "mobile first" approach of serving up mobile by default and adding in extra JS/CSS/etc if a larger screen is detected. Also, I have to say that of all of the mobile OPACs I've seen, the ones that were developed through a process of "how can we shrink this desktop page down to fit on a mobile?" rather than "what information do we want on a mobile and how can we best display it?" are uniformly crappy. Admittedly, many of those desktop OPACs are pretty crappy to begin with,4 but even with Koha it would be best to take a look at mobile design from scratch.
What features first? Search and biblio details seem obvious. What about user logged-in features?
I don't have any corroborating evidence at my fingertips, but my understanding is that mobile users tend to be looking up info like library hours and when their books are due more than searching. Which is to say - those things are probably important to be doing at the start, rather than leaving 'til later. It's probably useful to mention that one easy (and apparently relatively cheap) way to go mobile is to sign up with Boopsie [2] or LibraryThing's LibraryAnywhere [3]. They're perhaps less likely to be of interest to Koha libraries(?), but they can be useful for inspiration to copy too. :-) Also, I'll mention that I've been pondering the idea of writing a web app with Sencha Touch [4], in addition to the other mobile stuff. That wouldn't be until some time next year, so I'd be quite interested to see if anyone else did something along those lines. Anway, that was all that fell out of my head - hopefully it wasn't *too* rambling. :-) Cheers David [1] A good read, plus lots of links: http://www.lukew.com/ff/entry.asp?1436 [2] http://www.boopsie.com/libraries.html [3] http://www.bowkerinfo.com/offers/LibraryAnywhere/ [4] http://www.sencha.com/products/touch/