The vise trick can work, but it can be difficult to find a vise with nice sharp ends. The fixed cut flats are really thin. Likewise the bike can slip out its grip and you can end up with scratched paint or with getting smacked in the face by the bike you are leaning on. So the lesson is; using the real tool is always a better answer if possible. Almost any LBS will have one and would likely break the cup free for you and charge maybe $10 to do it. Then after you get it all back together you will need to have them tighten it for you, so another $10. You can get the Park branded tool with the pin spanner on the other end for less than that:

$17.55 w/ free 2 day shipping here:

http://www.amazon.com/Park-Tool-HCW-...bottom+bracket

While you are there...might want to look for other bike tools you will eventually need; A crank bolt tool, a crank extractor, a cassette remover, and definately a pedal wrench and maybe a set of cone wrenches if you wheels are not all sealed bearing ones....

Post more questions as they arise. Folks here are glad to help.