Thank you Doc and Sury
.Doc, I haven't altered the camera itself. I just use it in the 'Nightshot' IR mode (I believe this involves the IR filter being flipped out from in front of the sensor). Nightshot mode restricts shutter speed (1/30th I think) and aperture (F2.8 or thereabouts) so it would normally be totally blown in daylight. I have an adapter that allows ring filters to be added and I use a strongish ND filter and/or a Hoya R72 IR Filter. In the right conditions it produces very nice IR images. There is a nice tutorial here on using the V1 and how to process the images.
http://www.pbase.com/catson/color_infrared_workflow
It is a great shame that Sony did not continue developing this feature. I understand that there was a fuss about the cameras' ability to apparently see through clothing in some circumstances and this seemed to put an end to it. I will eventually get around to having a Nex or Alpha converted for IR, but the V1 is fun for the rare occasions that the the sun shines in the summer
.The V1 (and subsequent V3, which I think Yildiz had) were technological marvels. IR night mode and laser guided focusing with 5 Mp sensor! Review of it here http://www.digitalsecrets.net/Sony/SonyV1Review.html .
, but some just prefer the tail.