I have the same issue as well. It is an ACER netbook with HD2000 graphics. Minecraft 1.5.2 will give me around 30fps. Any version of 1.6 drops the FPS to 8. Simply unplayable.
Here is some information on my computer specs....
Aspire One 756-2623
Windows 7 Home Premium 64 bit
Intel Celeron 877 CPU
8GB RAM
Intel HD 2000 graphics
320GB hard drive