I will not talk about infrared photography more than this DIY tutorial needs. There are plenty of informations on the net, even here on instructable.com or in books.
There are a few ways to take infrared photos.
The simple way is to use a plugin, or play in Photoshop curves and colors, but that always just some fake copy of an original infrared picture.
Most common is to buy an infrared filter, put to your lens and use it. There are several disadvantages with this. First the camera has a built in IR filter to block the IR rays. Second, you can not see and focus too much when the filter is on, so need a tripod, frame the shoot without the filter, fix the tripod, attach the filter, set the shutter (which will be long regarding the dark IR glass) and take your shoot. The IR filter will allow only IR rays to go through but the IR blocker at the sensor is filtering out, so those bright whites will fade out a bit and still need a lot of Photoshop to have that stunning effect! If you have many lenses with different size, then more filter needed or conversion rings.
The best way to use an IR camera, dedicated for IR shooting, but those are rare and expensive...
And you all know what is left! Do It Yourself :)
Obviously nobody wants to ruin an expensive camera, especially if it won't take normal pictures anymore, therefore the best thing is to buy some good older camera which is easy to modify. To use any of my Nikon lenses on the infrared camera I picked an older, but not too old D80.
The requirements were to have a big enough LCD, handle lenses with no focus motor built in, and have some advanced options to set up the camera for IR pictures.
The used D80 was 130 euro. A used but perfect small IR filter was 18 euro.
The price of a good (HOYA) IR lens filter in 77mm size what I can use on my lenses and some additional converter rings cost 130+30 euro. See disadvantages above.