rerddap is now on CRAN http://cran.rstudio.com/web/packages/rerddap/ (GitHub: https://github.com/ropensci/rerddap)
It’s a general interface for working with ERDDAP servers - basically, many different groups provide data through this open source technology, and this package will let you query and fetch data from any of them. See here for an introduction to ERDDAP. Right now the package focuses on fetching NetCDF and csv data only, but many more data types are supported in ERDDAP.
We will soon depend on this package in rnoaa for fetching ERDDAP data in that package. I understand that xtractomatic will use this package as well.
Let us know if you use it and have any feedback.