how would I make snowflakes for a cake? I have seen that some people use royal icing.....what tip would I use and what recipe to make them hard enough for transfer?

Depending on the size of your cake you can use a #2 or 5, also you can cut them out of fondant or GP and sprinkle some decorators sugar to make them sparkle and let them dry. HTH

There are some patterns here in CC. You could use a fine tip and RI, let them dry and use in a cake.

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=90142
http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=90141
http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=90137

http://www.cakecentral.com/cake-photo-1289640.html

Hope that helps.