How to find out which package version is loaded in R?

 I am in the process of figuring out how to use my university cluster. It has 2 versions of R installed. System-wide R 2.11 (Debian 6.0) and R 2.14.2 in a non-standard location.

I am trying to use MPI together with snow. The code I am trying to run is the following

library(snow)
library(Rmpi)
cl <- makeMPIcluster(mpi.universe.size()-1)
stopCluster(cl)
mpi.quit()

It works without the problems on R 2.11. (I launch the script with mpirun -H localhost,n1,n2,n3,n4 -n 1 R --slave -f code.R). Now when I try to do it with R 2.14.2, I get the following message:

Error: This is R 2.11.1, package 'snow' needs >= 2.12.1
In addition: Warning message:

So it seems that R loads the package snow version compiled for R 2.11. I've installed snow under R 2.14 into my home folder and I added the following lines to my code:

libPaths("/soft/R/lib/R/library")
.libPaths("~/R/x86_64-pc-linux-gnu-library/2.11")
print(.libPaths())
print(sessionInfo())
print(version)

And the output before the error confirms that I am indeed running R 2.14.2 and my R packages folder is first in the search path. But I still get the error.

 So my question is how to check package version r? I can see with installed.packages all the packages which are installed, so maybe there is some function which lists similar information for loaded packages?