USinternetworking said it has picked Alistair Johnson-Clague to head the company's Siebel business unit. As an application service provider (ASP), USinternetworking hosts and rents Siebel applications--among other applications from different software makers--for customers who don't want to buy and manage business software internally. Customers access the Siebel sales applications remotely from their desktops. Before joining USi, Johnson-Clague was an executive at Avnet, an electronics, computers and software distributor.