Well the simplest way is to use either a pair of tweezers or a pair of needle nose pliers and "Ever So Gently" grab it and pull it out.
But this will only easily work if it is a Micro SD Slot and a Micro SIM. If it is a normal sized slot, but a micro card, then that will be a tad more complicated.
If your phone is still under warranty, or you don't feel comfortable using the tools on the device (as if you are not careful you can damage something), I would then suggest taking it to your carrier/manufacturer (if under warranty) or to a local tech (if not under warranty).