Do guys tell their female friends that they love them?

It heavily depends on the relationship. There is a lot of social pressure and expectation on him to say he loves her back when she says she loves him. However, he may not feel the same way, or be ready to admit that he loves her, or feel that he isn't good enough for her even if he loves her, or a variety of other scenariOS where he doesn't want to say those three Words. However, some guys are totally cool with hearing a girl say she loves him and accept that as a part of the relationship.

Best option: be in the relationship long enough for deep emotions to develop (probably 3-6 months, although this will vary based on the relationship), then do so privately for the first few times (ie, not in front of all his friends during the ball game) and be ready for that statement to shake things up in the relationship.