I think I would have it, I had mine between pregnancies as I was really unsure with the first one...
The carrier they use for the injection is the same one they use for the seasonal flu vaccines... it is only the strain that is different.
The main risk with the swine flu is that it lands on your chest, something that pregnant women are more prone to anyway, and as everything I have had in the last 2 years has involved my chest it is not worth the risk for me... The MW that I have come across seem to have been fairly non commital about whether you should have it or not, the GP may be more useful...