Enable Cheat Console
Start the game with the -enabledeveloperconsole command-line parameter. 

Example: "C:\Games\Dragon Age\bin_ship\daorigins.exe" -enabledeveloperconsole 

Then, while playing press ` (tilde) to open the console. You won't actually see it, but the console is running. Type any of the following cheat codes for the corresponding effect. 
 

Code:                                               Result:
runscript addxp #                              Add XP (# = Amount)
runscript zz_money #                        Add Money (# = Amount)
runscript zz_addparty [NPCName]     Add Party Member
runscript ai off                                  Disable AI
runscript zz_addapproval # ##           Add Approval (# = Member, ## = Amount)
runscript killallhostiles                       Kill All Hostiles