Had a great view just after sunset a couple of months ago of the ISS (very bright - brighter than Jupiter) being chased across the sky by the shuttle (less bright). No time to try to set up a telescope as it moves quite fast - just a couple of minutes from horizon to horizon. I think it'd be very difficult to find and track with a scope. Didn't realise at the time that detailed structure could be seen by those skilled enough to follow it. Here's a few web-links to galleries of detailed ISS photos & videos, mostly taken with web-cams & backyard telescopes (down to 114x900 newts!):
http://www.satcom.freeserve.co.uk/one.htm
http://www.esa.int/esaCP/SEMY46XAIPE_index_0.html
http://iss-transit.sourceforge.net/
The last link includes sun & moon transits by ISS, which give a good idea of the relative size of the ISS. There are lots more sites.......
Cheers -