QUOTE(WenRI @ Jun 10 2008, 02:05 PM)

if you need a visa to enter any europen countries, there is nothing to do with uscis.
uscis isn't the one issues you the visa you need.
Many consulates since you are asking the visa from here, required that you show proof of residency in the US, that is why the unexpired green card is needed. So in some way yes, in the other way is a no because to Europe most of their entry rules are based in your nationality not in your residency, except Mexico and Canada that once you are a US resident holder then you are free to enter without a visa restriction.
If you are going to several countries in Europe, remember the rules with the Schengen countries. Asked the one where you going to enter if that so, if not then asked directly to each consulate and see what is their answer here in the US. Most probably would be good that you obtain the I-551 stamp in your passport to process a visa if its required.
Example, when I checked/and later asked for a visa to India both statements were that I need to show proof of US residency e.g. Green card along with my unexpired passport for visa processing.
Good luck.