This book consitutes the refereed proceedings of the 5th International Conference on Intelligence in Services and Networks, IS&N'98 in Antwerp, Belgium, in May 1998. IS&N'98 was devoted to Technology for Ubiquitous Telecom Services. The 40 revised full papers presented in a homogeneous style and editing were selected from more than 80 submissions. The book is divided in sections on quality of service, service management, agent technology and applications, architechtures, mobility, platforms, electronic commerce, service creation, network management, gateways to CORBA, and security.