For alanswan's pictures, one of them, didn't exactly do the other because Auto WB doesn't work, at least I can't figure out how to get rid of the colour cast. Will be using another of my pictures to illustrate what the PP workflow should achieve and what it looks like:
*****
Step 1 - Use Hue/Saturation tool in PS, master channel, dial in -50 value
You get this, which still has a colour cast, but not as strong. With a custom WB you should get a different look, I'll show later.
*****
Step 2 - Auto Levels (Shift + Ctrl + L is the shortcut)
You'd be surprised how well PS adjusts IR photos to the correct tone if your WB is slightly off, if Auto Levels fail, Auto Colour works fine too.
*****
Image has changed drastically, but is the wrong tone, no idea why. Auto Colours here also yielded nothing. But at least the clouds are appearing correctly - white.
*****
Step 3 - I attempt to make it the correct IR tone, though the result will be different, since the trees are still with colour cast:
Hue/Saturation tool, Hue +100, Saturate + 20, master channel
*****
Step 4 - in IR , you have a lot of room for playing around, when I first started I didn't care about the colour cast, just abused the surreal effect, so all this is just the traditional style of PP, you actually have your own artistic freedom to do what you want to the photo so long as you're happy with it. But anyways, the point is, Highlight/Shadows will do a lot for your picture, especially since IR captures the tones in the sky very well:
Using the Highlight/Shadow adjustment tool, Shadows lifted by 15, Highlights recovered by 20, midtone contrast +10
You can see a more traditional IR look emerging.
*****
Step 5 - You should use curves for best results, but I'm not really feeling very well, and this scene does not really work well in IR, so I just bump up the contrast by 25.
****
Still not the correct look, but at least it looks a bit more like IR.
Must emphasize the importance of a custom WB here, even if you do not get the correct tone with the custom WB, i.e. still white images, the idea is that the color casts on the trees (a very important part of IR's signature look) will be easily PP'ed away, as compared to not having custom WB.
contrast +25
I still say Raynox DCR-250 works better on prosumer, on the FZ7 at same aperture the DOF is more:think: 
