Does anybody know of women scamming american men to come to the USA?

A russian woman contacted me on yahoo personals and we've been talking for about a month..didn't take long she said she was falling for me and then asked for money to send her here to america to see me..I said no way i'll send you money..but she keeps writing to me tho..for various reasons i think she is scamming me to come here or just take my money and run..anybody else here been dealing with such a thing also? and could you give me her name if so..been hearing alot lately about the scams from women in different countries doing this..thanks