it's possible to have platonic friendship between men and women.
it's ok to go out ba, esp if both are still single. it really
depends on the individual to make sure the line is
not crossed.
if the guy has developed feelings for u and wants to be a
couple, he might be more obvious.. e.g. do many things for u..
try to put his arm ard ur shoulder... or hint to u abt getting
tog...
if he's already done these things, then maybe do what
whiskers has suggested. sounds very diplomatic. and it can
also give the guy a way out if he's really fallen for
u and is feeling embarrassed tt u dun like him back. :)