To generate an executable image that can be randomly rebased at load-time by using the address space layout randomization (ASLR) feature of Windows Vista,  use the $SetPEOptFlags directive, or use the $DYNAMICBASE directive, which is new on Delphi 2007.

To do so, use either
{$DYNAMICBASE ON}

or

{$SetPEOptFlags $40}

or

{$SetPEOptFlags IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE}