You can certainly install (for most miners - this is just copying the .exe) on computer A.
You can then run that program from computer B using Windows file sharing or Linux file sharing (CIFS/SMB/NFS).
Example:
From Computer B:
\\computerA\c$\bitcoin\poclbm.exe --
For all intents and purposes, poclbm.exe is "installed" on computer A but being run from computer B. poclbm.exe is not the best example here, though - it has quite a few supporting files that are required. This method will probably not work with poclbm, but will work with ufasoft's miner or something similar.
For poclbm, you would need to map a network drive on computer B like this:
net use Z: \\computerA\c$\bitcoin\
Z:
poclbm.exe
