The Microsoft Lync Server 2010 Planning Tool has made it out of beta and is available to download here, http://www.microsoft.com/downloads/en/details.aspx?FamilyID=bcd64040-40c4-4714-9e68-c649785cc43a.
The Planning Tool will recommend a topology and out the XML for the Topology Builder based on questions you answer about your Organisation. The suggested topology includes most things you need to know; server specifications; IP addresses; host names; and firewall rules.
Site Topology:
Edge Network:
The topology can be exported straight to Visio which is great.
Microsoft Lync Server 2010 Planning Tool:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=bcd64040-40c4-4714-9e68-c649785cc43a.
Daniel Noakes