you can sure try to find out pre-ultrasound, but i wouldn't go out and buy pink or blue yet! there are tons of those "tests" like hanging your wedding ring over your belly (as someone said)... obviously those aren't very accurate.
That "Chinese Calendar" out there supposedly tells you gender depending on your birthday and month of conception... but in my experience it's never been right for the people i know!
They have those new over the counter tests now - but I was told my my doctor, and a few other sources when i researched it, that they're only about 50% accurate... which means they're wrong 50% of the time! Not much help in my opinion.
I know how hard it is to wait!! it was excruciating for me... i got to find out at my 20 week ultrasound (we're having boy/girl twins!). i've know women who's babies aren't cooperative enough and they have to wait until even later! I can't imagine!
as far as feeling unprepared for a certain gender: i was the same way with girls - i have no sisters, mostly boy cousins, and my parent's friends all had boys when i was growing up! but then i met my step-daughter (she was 2) and the thought of how to relate to a barbie-loving little girl scared me - but i got past the fear of the unknown and we have fun! She's 11 now and our relationship has turned out great! If it turns out that blue is in your future - I'm sure the same will happen for you, you'll learn to relate to him in a whole other way and it'll be the most natural thing in the world :)
If instead you're seeing pink - God love ya... i could never handle 4 girls!!! :)
I'm sure either way, soon you'll never be able to picture your life without him/her!
Good luck! Here's to a healthy, happy 9 months!!