I'm looking into some options for a mapping project (web, probably HTML5 Canvas based). Ideally, we are creating a navigational map (i.e. Google Maps) that would have our own very simple imagery (not satellite), but we are looking into ways of getting state / city lines, and maybe other important features. Does anyone know of a good database or project that contains this data correlated to longitude and latitude? Or are we looking at potentially drawing these lines ourselves?
http://openstreetmap.org should have what you need.
There is a huge amount of choice available, but it really does depend on exactly what your looking for, what level of detail and which countries.
One of the first places you'll want to look is open geo:
These guys have links to all the open source geographic stuff that's available more or less.
second to that is the OS-Geo consortium:
Again these guys maintain pre-made kits and links to the majority of data & applications available.
Once you go beyond here, then you likely will need to start looking at country organisations like the USGS:
and
http://egsc.usgs.gov/isb/pubs/factsheets/worldmaps.html
you'll most likely also want to take a look at some of the country specific data sets available such as the UK's ordnance survey:
http://www.ordnancesurvey.co.uk/oswebsite/products/os-opendata.html
and the USA Tiger data sets:
http://www.census.gov/geo/www/tiger/
finally, you could take a look at the likes of "Open street map" (And other similar products)
Open street map originally set out to cover the UK, but seems to be going at least Europe wide now (Maybe even world wide)
This is all I can remember off the top of my head at the moment, but one other tip I'll give, sites belonging to the top GIS software providers such as ARC-GIS & Mapinfo all have lists of mapping data providers on their websites, and some even have free data available too, an afternoons browsing should uncover you a lot of sources.