Official download pages:
TechCenter Lync Downloads Server and Client Update Downloads
Latest CU downloads

Deployment media:
Microsoft Lync Server 2010 180-Day Trial/Evaluation
Microsoft Lync Server 2010 Group Chat
Microsoft Lync Server 2010 Group Chat Admin Tool
Microsoft Lync Server 2010 Planning Tool (RC)
Microsoft Lync Server 2010 PIC Provisioning Page
Unified Communications Managed API 3.0 Runtime
Unified Communications Managed API 3.0 Software Development Kit
Office Communications Server 2007 R2, Communicator Mobile Component Package For Lync Server
Microsoft Lync Server 2010 Capacity Calculator
Microsoft Lync Server 2010 Bandwidth Calculator
IM an Expert for Microsoft Lync Server 2010
Microsoft Lync Server 2010 Web Scheduler

Desktop client installation media:
Microsoft Lync 2010 client Trial x86
Microsoft Lync 2010 client Trial x64
Microsoft Lync 2010 Group Chat Client
Microsoft Lync 2010 Attendant x86
Microsoft Lync 2010 Attendant x64
Microsoft Lync 2010 Attendee – Admin Level Install
Microsoft Lync 2010 Attendee – User Level Install
Microsoft Lync 2010 Phone Edition for Aastra 6721ip and Aastra 6725ip
Microsoft Lync 2010 Phone Edition for Polycom CX500, Polycom CX600 and Polycom CX3000
Microsoft Lync 2010 Phone Edition for Polycom CX700 and LG-Nortel IP Phone 8540

Mobile client installation media:

Testing and Training:
Microsoft Lync Server 2010 TechEd Videos fall 2010
Microsoft Lync Server 2010 On Demand Labs
Microsoft Lync 2010 Training ppt’s
Six Steps to a Successful UC Rollout
VHD Test Drive – Lync Server 2010 VHD

Troubleshooting
Microsoft Lync Server 2010 Resource Kit Tools
Microsoft Lync Server 2010 Best Practices Analyzer
Microsoft Network Monitor
Microsoft Network Monitor Parsers
Lync Microsoft Network Monitor Parsers
PortQry Port Scanner Version 2.0
Lync Server 2010 Monitoring Management Pack
Lync Server 2010 Stress and Performance Tool

White Papers and Technical Documents:
Microsoft Lync Server 2010 features and how to configure them
Microsoft Lync Server 2010 Documentation for IT Pros
Phones and Devices Qualified for Microsoft Lync
Microsoft Lync Server 2010 Protocol Workloads Poster
Microsoft Lync Server 2010 Visio Stencil
Microsoft Unified Communications Open Interoperability Program
Deploying the BIG-IP LTM with Microsoft Lync Server 2010
Deploying Citrix NetScaler for Lync Server 2010
Microsoft Lync Server 2010 On Prem or wait for Lync Online?
Microsoft Lync 2010 Pricing and Licensing
Microsoft Lync 2010 Licensing Explained
Configuring Microsoft Lync Server 2010 to Support Communicator Mobile for Java and Communicator Mobile for Nokia
Server Virtualization in Microsoft Lync Server 2010
Delivering Microsoft Lync with XenDesktop 5
Polycom and Microsoft Lync 2010 HD 720p with native RT-video
Miercom PBX benchmark test of Lync Server 2010
Microsoft Lync Server 2010 Security Guide
Microsoft Lync 2010 Pilot Success Kit

PowerShell Scripts:
Official Lync Server 2010 PowerShell Blog
Lync Server 2010 PowerShell quick reference card
LyncAddContacts.vbs – VBS Script to add Groups to multiple contacts
SCRIPT: Set-Lync2010Windows2008R2Features.ps1
SCRIPT: List-UnusedNumbers.ps1
SCRIPT: Set-GlobalVoiceRouting.ps1
SCRIPT: Disable-AdDisabledCsUsers.ps1
SCRIPT: UserSetupScriptGeneric.ps1
SCRIPT: Reset-UserPolicies.ps1
SCRIPT: LyncVCFGConverter.ps1