Heat transfer, or T-shirt vinyl, is quickly becoming one of the most popular types of vinyl.  This particular type of vinyl is designed specifically for attachment to fabric, hence the term T-shirt vinyl. 

There are a few different manufacturers of this vinyl.  One of the best all around vinyls is Siser Easyweed.  T-shirt vinyl is a little bit different beast to work with compared to your average sign vinyl like Oracal 631.  Weeding of T-shirt vinyl is really far more difficult but Easy weed is the easiest of all the heat transfer products to work with. 

The other thing that make is that you have to do everything backwards.  Working with sign vinyl is a WYSIWYG (What you see is what you get).  Heat transfer vinyl is a WYSITMIWYG (What you see in the mirror is what you get).  Sign vinyl peals off and sticks on just like any sticker.  T-shirt vinyl gets flipped over and ironed on. 

This whole concept can be a little intimidating at first.  Working with a Cricut and a Cricut cartridge you have to use the flip feature and spell everything backwards.  This is where a Silhouette machine or a Cricut with SCAL will really shine.  You can set up your entire design how you want it to look and then flip the entire thing at once.  This is much easier.  If you have ever tried to spell several words backwards with out errors you know exactly what I mean. 

The transferring process is quite easy.  Easyweed has a clear film over the front that acts like backing when you are cutting and like transfer tape when you are transferring.  This part of the puzzle also has a pressure sensitive carrier which helps the cutting to stay positioned before and during the transfer process.  You simply just follow the manufactures recommendations and iron it on. 

There is a bit of trial and error involved.  The recommendations are really just guidelines to get you close.  Sometimes you may need to adjust your heat or overall ironing time.  With a little experience though this can get easier.