[R-sig-Geo] R spatial newbie seeks advice r.e. esri data-compatible packages

[icosa atropa]

I'm new to R's spatial facilities.  I've been reading the r-sig-geo
mailing list for a week or two now, and I could use some advice.

I've decided to use R for a ArcGIS class project.  I spent today
reading R spatial package docs, and I'm a little confused as to what
work has been merged or duplicated, and what the most active tools are
for certain tasks.

To start with, I would like to read and write from ESRI formats such
as shapefiles and coverages. For shapefiles i find the
"shapefiles" and "maptools" packages; for coverages, I find "RArcInfo".

For datum and projection conversions, I found that both "rgdal" and
"sp" provide some functionality.

Any advice on where to start?
Thanks,
christian