MBTiles

MBTiles is a storage and exchange format which arranges raster and vector tiles in a SQLite file.

Specs. and references:

Converting MBTiles

GDAL - Converter to read MBTiles, especially From WMS to MBTiles and From GeoTIFF to MBTiles
MBUtil - see below.
"Convert ESRI's Vector Tile Package (VTPK) to MBTiles" (Austrian basemap): https://github.com/BergWerkGIS/vtpk2mbtiles (CSharp)

Generating MBTiles:

MBTiles can be read from and/or is delivered by:

MapCache
mbtilesviewer - http://viswaug.wordpress.com/2011/06/28/mbtilesviewer/
ArcGIS Dynamic Map Services. See TileCutter.
MapBox Online [2]. Publishes maps in the cloud. MapBox Hosting uses TileStream but adds many features and is a hosted service.
TileServer-PHP [3] (PHP). Deliveres pre-rendered map tiles in OGC WMTS standard made with MapTiler, GDAL, or available as MBTiles files.
TileStream [4] - High-performance map tile server powered by MBTiles files (Serverside Javascript). Can be used in OpenLayers, Google Maps, Modest Maps, and other Javascript APIs. Wax (Javascript lib) enhances it.
TileStache [5] (Python). Is aka successor of TileCache, based on Mapnik; reads MBTiles (metatiles) format. Generates vector tiles from OGR datasources in GeoJSON (usable in Polymaps). Writes (caches) to disk, Memcache, Amazon S3, MBTiles. Serves tiles in Google-style spherical mercator projection and WGS84 lat/lon projection. Runs from CGI, mod_python, or Gunicorn WSGI.
GDAL [6]. GDAL2Tiles utility. Is used in turn e.g. by QGIS and UMN MapServer.
MBUtil [7] (Python) by klokantech. Exports MBTiles to disk (as plain raster files) and imports/packages from disk to MBTiles format.
python-mbtiles [8] (Python) by PerryGeo.
https://github.com/pbarry/MBTiles-extractor

One can also use MBTiles files offline on mobile devices with the MapBox iOS SDK or on Android (OsmDroid).