Privacy Protection for Handheld App Webpage Access?

Prof. Jonathan Ezor, Touro Law Center asks: "Is anyone using a third-party application on a Treo, Blackberry or other handheld to access login-protected Internet resources such as eBay, satellite radio services, and the like? (I'm thinking of programs like Abidia or MiniXM.) If so, have you thought at all about who might be running those services, and who is getting access to your login information via the service in addition to the site you want to access? If this does concern you, what have you done about it?"