The internet plays an important role for scientific discourse and the distribution of geospatial data. Inevitably there are some very good tutorials available online. The best ones have been produced by major players in the industry. Their main drawback seems to be that they tend to emphasise the positive aspects of the application of the technologies and don't always provide a full assessment of the limitations. For that reason you should not rely solely on them in your studies.  
The ESRI Virtual Campus delivers a comprehensive suite of online courses on ArcGIS products, issues in GI science and applications of GIS.

Source: ESRI. <> URL last accessed 2005-10-9

  Recommended Tutorials

NASA Earth Observatory is a rich source of scientific information, news and imagery on Earth observation by remote sensing.

Source: NASA. <> URL last accessed 2004-9-15

Fundamentals of Remote Sensing is a well-illustrated introduction to remote sensing.

Source: Canadian Centre for Remote Sensing. <> URL last accessed 2005-8-31

The GIS Files offer a data-centric approach to GIS.

Source: Ordnance Survey of Great Britain. <> URL last accessed 2004-9-15

The GIS Primer is one of the early GIS tutorials that is mainly text based but still worth visiting.

Source: Buckley, J., 1998. The GIS Primer. Colorado: InnovativeGIS. <> URL last accessed 2004-9-15

GIS Self Learning Tool provides some neat learning materials on raster and vector GIS.

Source: University of Melbourne. <> URL last accessed 05-01-2008

UNESCO GIS Training Module is a helpful tutorial from an organisation and a department (oceanography) not normally associated with GIS.

Source: UNESCO. <> URL last accessed 05-01-2008

Remote Sensing Tutorial is the 'original' tutorial on remote sensing.

Source: NASA / USAF. <> URL last accessed 2005-8-31