Microsoft has a very interesting offering for small businesses called: Office 365. Basically, it’s MS Office for the Web. It integrates and complements the desktop version of the suite by using Web Apps. You get your basic set of business tools such email, web conferencing, documents, and calendars for a monthly fee. It’s a direct competitor to Google Apps.
I’ve seen earlier versions of that product, and I can say that it gives Google a run for its money. It’s a very good option for a small business
You can try it free for 30 days. It might be worth to check it out.