Tutorials to handle spatial data in R?

This question has been converted to Community Wiki and wiki locked because it is an example of a question that seeks a list of answers and appears to be popular enough to protect it from closure. It should be treated as a special case and should not be viewed as the type of question that is encouraged on this, or any Stack Exchange site, but if you wish to contribute more content to it then feel free to do so by editing this answer.

There's quite a few resources for learning 'spatial' R online, some of the better ones are:

  • spatial-analyst.net
  • A really solid blog post by Frank Davenport, with notes on some basic spatial data manipulation in R
  • R Spatial Tips (Internet Archive link, original site seems to be gone)
  • Barry Rowlingson's site containing some great examples and a cheatsheet

A couple I've found useful:

  • I'd strongly recommend Analysing spatial point patterns in 'R' by Prof. Adrian Baddeley at the CSIRO in Australia. It covers the spatstat module in depth and I think it's a great resource for cluster analysis.

  • Applied Spatial Data Analysis in R (Bivand, Roger S., Pebesma, Edzer J., Gómez-Rubio, Virgilio) and Spatial Statistics and Modeling (Gaetan, Carlo, Guyon, Xavier) are also both great books.

Few more from my side:

  • Virgilio Gómez Rubio's (he is the author of the famous/superuseful ASDAR book, mentioned in other answers) website provides materials to his tutorials from useR! conferences - slides, data and code are available.
  • Apart from ADAR, there is now new book 'An Introduction to R for Spatial Analysis and Mapping' by Brundson & Comber with code available for download.

  • CSDE (University of Washington) course on GIS has some spatial R materials, focusing on ESDA, GWR, spatial regression

  • Maps with R I (II, III) series of blog posts offer a lot of extensively commented code that you can learn from.
  • UC Davis Soil Resource Laboratory has a nice collection of tips and examples of spatial R
  • Francisco Rodriguez-Sanchez has a nice materials on 'Spatial data in R: Using R as a GIS'.