[R] Creating adjacency matrix from a data frame

[Thomas Jensen]

Dear R-list,

Sorry for spamming the list, but I am just learning how to manipulate  
data in R, so  if this is a trivial question I am sorry.

I have the following data which list the distance between capitals:

       		ida   	idb   	kmdist
7108  	"UK"  	"BEL" 	" 313"
7110	"UK"  	"FRN" 	" 365"
7116  	"UK"  	"POR" 	"1618"

I would like to convert this into an a valued adjacency matrix that  
looks like this:

	BEL		FRN	POR
UK	313		365		1618

The full data set has all possible pairings between countries, so the  
end goal should be a symmetric adjacency matrix.

Thank you,

Thomas Jensen