How to operate IPv6?

IPv6 is "IP with bigger address space", almost no difference with IPv4
bigger address space makes a huge difference

Base spec
NAT-free 128bit address, simpler base header, extensible header format
Enables many future application deployment and uses
Routing - OSPFv3, RIPng, BGP4+
QoS - diffserv, RSVP (separate effort from IPv6 itself), more friendly than IPv4
Mobility - mobile-ip6 (No foreign agent necessary)
Security - IPsec (separate effort from IPv6 itself)
A "fully conformant IPv6 implementation" must have IPsec code
Autoconfiguration
stateless autoconf, DHCPv6
Multicast - PIM, MLD (= IGMP)
Applications - HTTP, FTP, VoIP, whatever you do with IPv4
New applications would appear when IPv6 hits the critical mass