[R] select row

[Leonardo Lami]

Hi all,
I have a little problem selecting some rows from a data.frame.
I'd like to select the rows where a determinated column take a
partivolar value.

For example:
tab
          id       x       y
1    24-2005 1621814 4834991
2    24-2005 1621856 4834907
3    24-2005 1621763 4834956
4   25-2006 1622330 4835189
5   25-2006 1622533 4834834
6   25-2006 1622535 4834909
7   25-2006 1622543 4834803
8   28-2005 1622798 4835043
9   28-2005 1622299 4835129

I'd like to select the row where id=25-2006

I searched on the search of the R site but I did'nt find anything of simple.
Can someone help me?

Thank you very much
Leonardo