Number of packages at CRAN is increasing sharply. Therefore, it is hard to keep track of what is available to useR. Dirk has bundled up a script that generates a web page and RSS for tracking changes on CRAN, called CRANberries. Site is here, while a note on RSS can be found here. Great! Now you can monitor the vivacity on CRAN and try to know what is available.
I have answered question on using Computer Algebra System (CAS) in LyX via Ryacas. You can see the answer here. In summary, LyX has a way to work with different CAS internally, but I have shown how to use Ryacas via Sweave in LyX. I sent yesterday a note on the latter to Rnews. Stay tuned!