Installing R from CRAN Ubuntu repository: No Public Key Error

Question

I am on R version 2.13 and would like to update to a newer version in order to use some packages that depend on R>= 2.14.

I have the line to my sources.list file as

Answer 1

Much like others posted above, this one-liner seems to work well on Debian 6:

sudo apt-key adv --keyserver hkp://pgp.mit.edu:80 --recv-keys 381BA480

Executing: gpg --ignore-time-conflict --no-options
--no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver hkp://pgp.mit.edu:80 --recv-keys 381BA480 
gpg: requesting key 381BA480 from hkp server pgp.mit.edu 
gpg: key 381BA480: public key "Johannes Ranke (CRAN Debian archive) " imported 
gpg: no ultimately trusted keys found 
gpg: Total number processed: 1 
gpg:      imported: 1