My boss has the idea that he wants to host some companies emails on our small server with our exchange 2007 on SBS08. I was wondering what the best practice is to do so. Just add them to accepted domains, create mailboxes and set the correct email addresses? Thanks for your help!

Not a good idea. First - your licence for SBS isn't valid to do that. If you want to host mailboxes for other companies then you need to use full product, and you will have to be on a hosted licence agreement. That is a per monthly payment. Then you have the 75 user restriction. If you just add them as additional users, then everyone can see everyone else in the GAL, public folders, distribution lists etc. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

first go for exchange upgrade. you need to move from SBS first.Dishan M. Francis - (http://www.rebeladmin.com)

Depending on number of users consider recommending BPOS/Office365, have a look at the MS site for it and see what you think yourself. http://www.microsoft.com/online/trial-bpos.mspx And as the others wrote, if you do want to host internally you need to get the full product. There are some options for doing hosting with Exchange 2007 addresslist seggregation and Exchange 2010 hosting setup to look into as well if you proceed this way. /MartinExchange is a passion not just a collaboration software.