Policies and Procedures

Sounds like you need an Internet and Email Policy or something similar. Techrepublic have a good doc in the downloads section.
PDA's is not an issue yet for us , and we have got all users to sign a policy that they do not download programmes from the web

This one is pretty much dictated by management philosophy. However, as a general guideline, acceptable use of work computers should be those tasks that contribute to getting "work" done. While many would like to stream audio, stock quotes, chat, etc., all these things open systems up for malicious code to be run on the system doing so and can then spread throughout your network. Depending upon the size of your organization, you should have dedicated system administrators who control what software is loaded on systems, as authorized by upper management. An enterprise server or two hosts all authorized software and only certain users are then authorized to install that software. This policy should apply to ALL areas, with the exception of your developers, R&D and system adminstrators, who perform their tests on non-production hosts before releasing them for public installation. All systems connected to your production network adhere to that software policy, again controlled by your sysadmins. Company owned PDAs are no exception. Bottom line, company owned assets are used to carry out company business. That's not to say you can't allow personal email, chatting, streaming audio etc., but that's not what people are being paid for. Butit can have both a negative and positive impact on productivity so your individual (business) reality dictates acceptable use. Be sure to let your folks know that other than business use is a privilege, not a right and may be terminated depending upon business impact.

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