The 'temp' folder is whereapplications store files during intiial
installation. Most are deleted as soon as installation has been completed.
In most cases it is safe to delete files from the temp directory *But* to be
on the safe site delete them to the recycle bin (don't permanently delete
them by pressing 'shift + Del') Leave them in the recycle bin for a week and
see if you expereince any problems. If you don't then you can empty the
recycle bin.
Personally there is absolutely nothing in my 'temp' folder but if there were
and i were to delete it i would take the precautions mentioned above.