[R] Data frame to matrix - revisited

[Jagz Bell]

Hi,
I've tried to look through all the previous related Threads/posts but can't find a solution to what's probably a simple question.
 
I have a data frame comprised of three columns e.g.:
 
ID1 ID2 Value
a b 1
b d 1
c a 2
c e 1
d a 1
e d 2
 
I'd like to convert the data to a matrix i.e.:
 
 a b c d e
a n/a 1 2 1 n/a
b 1 n/a n/a 1 n/a 
c 2 n/a n/a n/a 1
d 1 1 n/a n/a 2
e n/a n/a 1 2 n/a
 
Any help is much appreciated,
 
Jagz