Office 365 Migration

I am doing the 30 day trial of Office 365.  I have 25 users at my business but don't want to impact business yet.  Is there a way to migrate 2 or 3 of us over so that we are using full office 365, Online Exchange, etc with the full features?  Currently our exchange is hosted through a 3rd party cloud service.  Email is not saved in a local PST file