1. A computer program product comprising a computer useable storage medium to store a computer readable program that, when executed on a computer, causes the computer to perform operations comprising: link a web address entry of an address book in an email client to service information from a service registry, wherein the service information corresponds to a web service; generate a user input form with a custom input field corresponding to the service information for the web service; and invoke a service request for the web service via an email message according to user input via the custom input field of the user input form.