At the start of a battle where you can use the Deep Strike rules, you can declare that your Space Wolves are deploying by landing in drop pods from orbiting spacecraft. Models doing this deploy using the Deep Strike rules in the Warhammer 40,000 rulebook.
Only the following can deploy from drop pods. No other models in the army can be used in this mission (they stay aboard ship): any Space Marine model in power or Terminator armour, Space Marine Scouts, Dreadnoughts and Land Speeders.