Lattice is best thought of as an implementation of Trellis Graphics
  for R. Its interface is based on the implementation in S-PLUS,
  but there are several differences. To the extent possible, care has
  been taken to ensure that existing Trellis code written for S-PLUS
  works unchanged (or with minimal change) in Lattice. If you are having
  problems porting S-PLUS code, read the entry for panel in
  the documentation for xyplot. The Lattice website
  referenced below has some useful material as well.
  Most high level Trellis functions in S-PLUS are implemented, with the
  exception of piechart.
  Lattice is built upon the Grid Graphics engine for R being developed
  by Paul Murrell and requires the grid add-on package.
  Type library(help = lattice) to see a list of (public)
  Lattice graphics functions for which further documentation is
  available. Apart from the documentation accompanying this package, 
  several documents outlining the use of Trellis graphics is available
  from Bell Lab's website that might provide a holistic introduction to
  the Trellis paradigm. Lattice also has a website with some tips.
Cleveland, W.S. (1993) Visualizing Data.
Becker, R.A., Cleveland, W.S. and Shyu, M. ``The Visual Design and Control of Trellis Display'', Journal of Computational and Graphical Statistics
  Lattice Webpage:
  
xyplot.  To learn how to customise the Graphical parameters used by the Lattice
  functions, see trellis.par.set.
  To learn how to initialise new devices or change the settings of the
  current device, see trellis.device
  To learn about sophisticated (non-default) printing capabilities, see
  print.trellis. Also described there are the
  possibilities to enhance the plots thus produced (using locator
  like functionality).
Here is a list of `high level' functions in the Lattice library with a brief description of what they do:
Univariate:
  barchart bar plots
  bwplot box and whisker plots
  densityplot kernel density plots  
  dotplot dot plots
  histogram histograms
  qqmath quantile plots against mathematical distributions
  stripplot 1-dimensional scatterplot
Bivariate:
  qq q-q plot for comparing two distributions
  
  xyplot scatter plot (and possibly a lot more)
Trivariate:
  levelplot level plots (similar to image plots in R)
  contourplot contour plots
  cloud 3-D scatter plots
  wireframe 3-D surfaces (similar to persp plots in R)
  Hypervariate:
  
  splom scatterplot matrix
  
  parallel parallel coordinate plots
  
  Miscellaneous:
  rfs residual and fitted value plot (also see
  oneway)
  tmd Tukey Mean-Difference plot
  Lattice also has a collection of convenience functions that correspond
  to the base graphics primitives lines,
  points, etc. They are implemented using Grid graphics,
  but try to be as close to the base versions as possible in terms of
  their argument list. These functions have imaginative names like
  llines are are often useful when writing (or porting
  from S-PLUS code) nontrivial panel functions.