Is there a scientific opinion about the connection between Asperger Syndrome and AD(H)D? I have Aspergers and ADD. When I read autobiographies (most of all by female aspergers) I often think that they have actually at least a mild form of ADD or ADHD, too. 

A German doctor (Dr. Helga Simchen) wrote she thinks that Asperger Syndrome should rather be on the AD(H)S spectrum than on the autism spectrum.
My personal opinion is: no. They're nevertheless different things.

But what is the current scientific standpoint about AS and AD(H)S?
There is a significant overlap between symptoms of classic Autism, Asperger syndrome, AD(H)D and OCD.
The following graph gives a good overview of how they are correlated at the behavioral and sensory level:

(source)

Further reading

Common brain changes found in children with autism, ADHD and OCD
The Co-Occurrence of Autism and Attention Deficit Hyperactivity Disorder in Children – What Do We Know?
Autistic traits in some children with ADHD
A Third Of Autism Cases Also Have ADHD Symptoms
Autism and ADHD: Overlapping and discriminating symptoms
Autism and ADHD Share Genetic Similarities
Timing of the Diagnosis of Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder