Warner Brothers has created a service called Red2Blu that lets you convert your HD DVD collection into Blu-Ray by sending them $5 per HD DVD title along with the paper insert from the case. You keep the disc, just send the cover art.

Combine that with iNetVideo.com, a clearing house for old HD DVDs. You can get some as low as $1.99.

Let’s say you want 300 on Blu-Ray. At Amazon, it’s $22.49. On the other hand, you can get the HD DVD for $1.99 at iNetVideo.com and upgrade at Red2Blu for $4.99. That’s a total of $6.98 for the movie, saving you $15.51.

Now, you’ve got to consider shipping costs - it’s $6.95 shipping for the Red2Blu conversion on an order up to 25 discs and the shipping from iNetVideo varies - so you wouldn’t want to do just one movie… but if you have several, like if you want all of the Harry Potter movies or something, you can save a bundle.