Patrick Grady wants to be your "virtual" personal assistant. He'll schedule your travel, entertainment, meetings--and even, very soon, your home repair. And he'll do it all through a simple Web interface that automatically keeps your calendar and alerts you if something changes. For now, Grady, 38 and dangerously hypercaffeinated, pitches only to big companies such as Motorola, Whirlpool, GlaxoSmithKline, and Hewlett-Packard; he has already scored a total of 500,000 subscribers in less than a year. Employers love Rearden's product because all work-related purchases are made according to policy. "It's a big idea," says Bruce Richardson, chief research officer of AMR Research. "He's serving highly mobile white-collar workers and appeasing their finance departments, too."