Popina Swimwear actually has a lot of really cute, modest, vintage-style swimsuits. I love this red Jantzen vamp.
Modcloth is where I've found most of the swimsuits I really like. Too bad they're all expensive. Here is Bathing in Beauty light blue velvet.
Beach Blanket Bingo.
Bathing in Beauty plum posy (adorable).
Bathing in Beauty cherry pie. This one might be my very favorite.
Last, but not least, I love love love these sandals.