Dell PC Suite installer is on the Streak itself. Plug in the USB, ignore the Windows message if it says it couldn't find/install the hardware properly (it will once PC Suite is installed), and on your phone say you want to give access to files.
Browse the removable disk drive on your PC and among the other folders on your SD card will be one with the 32MB PC Suite installer in it ready for you to copy across.
This is handy for deploying the software between 2 locations (home / work PCs, or home / parents, etc. etc.).