Creating Liquid

Ok heres my Idea I want make a website and it kind of has this oil in water look about it now what I want to do it make the background image(bits of oil splatter and the like) move like oil paint in water when you touch it similar to the effect here www.senocular.com/flash/source.php?id=0.176
except I dont want to have to drag the paint i want it to be pushed by the mouse and float away. also the liquid generate out of nothing I want it to actually change the shape of the background completly. basicly just like pushing paint around in the water. Oh and it dosen’t need to be beveled of look like anything cos my image is just blue. So yeh Big ask but any help advice tutorials would be great because i’m quite excited about the idea I think it would look great. Thanx