e-mail addresses

Hello,
I heard about the existence of a software (in Italy) which can list me worldwide e-mail addresses, simply following keyword input (i.e. It is supposed I am interested to search travel agencies e-mail addresses: I input in a box the ‘travel’ keyword and this software display any e-mail address related to ‘travel’ existing on the net).Its price is around $1500
Do you think this software is reliable? Anyone know about another similar software available in Internet, or anyone could suggestme another way to get e-mail addresses respect traditional e-mail locators (Bigfoot.com etc…which list e-mail address only if I input the name of business and not the keyword) ?