CRM for the services industry
I'm not aware of a specific information source focused on CRM for Professional Services - part of the reason being that there are so many different aspects of the 'Services' industry. Certain vendors (for instance Interface for Legal, Metavante and S1 in Financial Services, Cosential in AEC) have focused on particular industry sectors while other companies (SalesLogix, Siebel, Microsoft) have worked in conjunction with integrators or in some cases customers to develop specific functionality.
In terms of industry needs, the general scenario faced in Professional Services organizations include:
It is difficult to generalize since 'Professional Services' is so broad but hopefully this gives you at least a start.