One of the biggest problems I run into while wearing a rock climbing harness for tree climbing is that I have so many pieces of gear clipped to my belay loop the mess is nearly impossible to deal with. This modification pulls your lanyard attachment points to the sides of the harness and frees up room on your belay loop for your main climbing system. Now, I totally understand that adding lanyard attachment points to a rock climbing harness does NOT automatically make it a tree harness but I think this is one of the biggest distinctions between the two types of harnesses.
This tutorial does not require any sewing. All you need is your harness, 8-9 feet of webbing, and two rappel rings (this is the cheapest 32kn rated ring I have found: http://www.treestuff.com/store/catalog.asp?category_id=303&item=1684). You may have noticed that my personal modification has a buckle on it and this makes the setup much easier to use but this means I have to use BOTH rings at the same time. If I only use one of the rings and the un-rated buckle fails then I would fall to my death. But if you tie your webbing like in the video you do not have to worry about this! Now if I could just figure out how to add an adjustable bridge to my harness!
TREEfool 
Very interesting information.
Why is the video unavailable?
I temporarily removed it due to safety concerns but the concerns have been resolved so I should have the video up soon.
I just got myself some rings (25kn) and webbing (22kn) and came back to watch the video again and it`s gone:(
Would really appreciate it a lot if you put it back up! Just want to double check I`m doing everything correct.
Were the safety concerns about the weight being on the accessory loops when you hang vertical off something with your lanyard?
Ok, it is back up. If the accessory loops break the lanyard will still do its job (they are just used to keep it in a more comfortable spot) but the concern was about my recommendation to use a waterknot.