thanks mate...your purple/blue flowers look awesome. i bet the colour looks blue because of your WB setting.
same thing happened to me at my sister's wedding. my bro-in-law was wearing a purple tie and it came out blue in every pic. another guy who was taking pics with his D90 had the same result. but somehow yet another guy with his D80 was able to get it purple. only difference was that fella was using an external flashgun.
anyway the vignetting can be done with the camera itself on some lenses and filters but mine was done in LR 2.3....there are about 6 sliders under Vignettes and i slide them all to the left except the last one i slide to the right. you can mess with it and get different effects.