There is big news today in the Delphi world: a virus that specifically attacks Delphi installations, inserting a bit of code to embed itself in any application compiled by that Delphi installation. (more info here)
The virus adds code to SysConst.pas, which is then compiled in to SysConst.dcu. (Those are analogous to .c and .o, for those of you outside the Delphi world).
I immediately checked all of my machines (and all Delphi installations on them) and found them all to be clean; but I am obsessively careful about what software I run, and use antivirus software as a second layer of protection on top of that. All Delphi shops should check for this ASAP.