Only minimal sewing experience is needed, and in a pinch you could even substitute fabric glue without too much difference. The illustrating photos were taken with some creative use of Photo Booth, but hopefully they are clear enough to help.
You will need:
+ approx. 3' x 1' black felt
+ batting (har har) or cotton balls (I used stuffing from an unwitting pillow - you won't need more than about two handfuls)
+ needle and thread
+ scissors suitable for cutting fabric
+ scrap paper and a pencil or pen
+ ribbon (about 3 yards)
+ seed beads (I used 6 pairs in different colors, so 2 red, 2 yellow, 2 blue...)
+ an embroidery hoop (I used a 12" from a thrift store)
+ little bells, if you want them (I used 6 that were about 1/4" in diameter)
+ spray paint OR smallish paintbrush and acrylic paint in the color of your choice (you will use these to paint the wooden hoop)
+ small ring (key ring, carabiner, wooden napkin ring, etc., from which the mobile will hang)
This is my first Instructable, so if it is unclear in spots, please let me know and I'll do my best to clarify.
Step 1: Making the pattern
Cut it out halfway, then fold it in half to make sure it will be roughly mirrored on the other side. I had to adjust the ears and the tips of the wings on mine. Then finish cutting out the bat.
This cutout is your pattern.