Install a sme 5.5 on it, and as long as you got 128M ram, it will do the job fine for you.
I have try that setup on a P233 PC (not a PII) with 128M ram, and no one in the office said a word on the slow Internet again, as the proxy did cache up the pages.
(IN my point of view, a P233 is not faster than a P166 much.......)
They will just say that the file share is slow, even the e-mail server run well.
Just try not to let you user the load file into ther server and it will just work well !!
Best Regards,
Paul T.C.Fung