[R] R package that translates zip codes into longitude and longitude

[Nicola Ruggiero]

Hi there,

I'm looking for a R package that would enable me to add a column to a
data.frame that is itself a translation of zip codes into longitude
and latitude. The column in the data.frame looks like this [begin
quote]:

waltham, Massachusetts 02451
Columbia, SC 29209

Wheat Ridge , Colorado 80033
Charlottesville, Virginia 22902
Fairbanks, AK 99709
Montpelier, VT 05602
Dobbs Ferry, New York 10522

Henderson , Kentucky 42420

[end quote:] The spaces represent absences in the column. Regardless,
I'm told that there is such an R package. I'm just having trouble
locating it on Google.

Warmly,
Nicola