Hardware requirements :
# Processor 64-bit, four-core, 2.5 GHz minimum per core.
# RAM 4 GB for developer or evaluation use, 8 GB for single server and multiple server farm installation for production use.
# Hard disk 80 GB for installation
For production use, you need additional free disk space for day-to-day operations. Add twice as much free space as you have RAM for production environments.
Software requirements :
# The 64-bit edition of Windows Server 2008 Standard with SP2. If you are running Windows Server 2008 without SP2, the Microsoft SharePoint Products and Technologies 2010 Preparation Tool installs Windows Server 2008 SP2 automatically.
For more see : Prerequisites for SharePoint 2010