What font does the character of an empty heart come from?
That particular heart is from Arial Unicode. PCs (and I believe Macs as well) should come with it installed. It was developed as a sort of universal language font that contains all the characters for most languages. It’s about 22Mb, vs. 50kb for a typical font. You can access all the Arial Unicode characters through the Character Map (you might already know this) Start menu –> All Programs –> Accessories –> System Tools –> Character Map. If you are looking for open hearts in other fonts – particularly in free fonts that often don’t come with full sets of symbols, you might find them attached to one of the normal keyboard characters.