I am currently helping a new company get started. They wanted an 0845 number with cheap outgoing calls and the ability to call potential sales back free of charge from the website.
If you want to set up a phone system, but have little capital I must recommend getting an account with
www.voiptalk.org and then setting up an account with
www.easypabx.com. It allows you to have call backs, customer queues and hold messages, virtual fax, etc etc etc.
It's a little complicated to set up but if people want advice, please let me know.
Tom