Well, asperger's is part of a more broad category now: pervasive developmental disorder.
here's the DSM for sociopathy
here's the DSM for pervasive developmental disorder (have to scroll down to 'diagnostic criteria')
criteria for Autistic Disorder
There's quite a difference. To generalize, personality orders aren't about performance, but more character, while developmental disorders can affect performance.
There's actually a lot of controversy about personality disorders... the general criteria for a mental disease requires that the disease cause distress. Classically, that meant to the person suffering the disease, but often with personality disorders it's others who suffer. So is it right for psychiatrists to require sociopaths get treatment or should the just be treated like adults responsible for their actions?
High functioning asperger's may look similar to (the more typical) mild cases of sociopathy on the outside, but I'd speculate that subjectively, it's experienced very differently.