I was watching this video: http://www.youtube.com/watch?v=7RDr--UZFy0

At 1 minute 58 seconds, the historian mentions that the Franks were well known for a particular type of sword, which they developed. I was wondering, what type of sword would that be? The pattern welded Spatha was developed by Franks? Is that accurate? Or is the History Channel up to it's antics again?

I've heard that some Viking swords were made by Franks, but the documentary is set a bit before the Viking Age. It was my impression that the Germanic Tribes during the Migration Period all used essentially the same types of spathas, with the distinctive sandwich guards and possibly rings on the pommels. I don't think that there is a specifically Frankish sword type.

Is there a distinctive Frankish style of sword? I'm interested to see some other opinions out there.

Haven't heard of a Frank-specific sword. There is the famous "frankish axe", of course. It is possible that Kenneth Harl simply goofed and mixed his weapons up during the interview (heck, maybe he hasn't lived it down).
Or maybe he was referring to the gradual tapering to many swords seen around the Carolingean period and later, since the term "Frank" and "frankish" persist much later?

maybe someone else has more details?

Well, you could say that "Ulfberhts" and similar swords are frankish, although frankish empire parted since then.

i'm not an authority on the subject but the research i've done indicates a frankish origin for the best pattern welded swords (read "most expensive") from about 600AD-the early viking age. it also seems that it was just the blades that were of frankish origin and the actual fittings were put on by smiths in the area where the buyer lived in.

again, this is just a projection from a little bit of research, but that is how it appears at least to me. again, not all pattern welded swords, it just seems that the most desirable ones were.