Sending outlook appointment +webmail

[Clive_S]

HI,

I live in the UK and use Outlook 2010, there are several ISP
available. If you change your ISP, you need to change your email
address AND if you can't send an email from abroad - have to use
Webmail. Also can't forward calendar appointments, etc.

What service would I need to look for to be able to send emails,
Outlook appointments, etc from either in the UK or abroad (when not
connected to my ISP)???

Does the service have a particular name, what would I search for??
Any suggestions appreciated.

Clive