Nowadays, the development of services that span over both the Internet and telephony networks is driving significant efforts towards the integration of services offered by IT providers with telecom operators ones .Web Services have often been recommended for providing, composing and realizing Telecom services but introducing them means facing up with several challenges. This work sharpens benefits and drawbacks of Web Service applications within a Telecom environment focusing in particular on JAIN SLEE architecture, which defines a standard environment targeted at communication-based applications..