you can press with anything you want- the only thing to really keep in mind with flannels are- they are a looser weave than the fabrics you are *used to* and will shrink more because of the looser weave- so pre-washing is recommended.
other than that- you can starch them to help with cutting-
you should use a new sharp needle-
i usually use a wider seam (1/2") because they fray more than regular cottons (again because of the looser weave)
they make wonderful, fluffy, soft, cozy quilts! i love working with flannels!