I did a bit of research online first. We opted for a non-religious ceremony, but there's lots of help with that as well, like lukyloo said. The way I figure it, there's three ways to exchange vows: where you and your DH read your own vows, where the officiant asks you to repeat after him, and where the officiant asks you a question and you answer "I do." Since we knew we'd be nervous, we went with the latter two, so we didn't have to memorize anything.
I think my vows might be on the shorter side, and they're definitely more irreverent than most, but hopefully it'll help you at least a little:
I, <full name>, take you, <full name>, to be my lawfully wedded wife, to have and to hold from this day forward, for better or worse, for richer or poorer, in sickness and in health, to love and to cherish, for as long as we both shall live.
Do you, Steven, pledge to support Christine in all things, to love her above all others, to listen to her when she needs comfort, and most importantly, to buy her milk because she’s too lazy to get it herself?
Christine, please repeat after me.
I, <full name>, take you, <full name>, to be my lawfully wedded husband, to have and to hold from this day forward, for better or worse, for richer or poorer, in sickness and in health, to love and to cherish, for as long as we both shall live.
Do you, Christine, pledge to support Steven in all things, to build him up when he feels down, to comfort him when he is sad, and most importantly, to think about buying him video games and Guinness beer, as long as the timing and budget are appropriate?
{Look to audience} Can you tell who wrote these vows?
Do you, Steven and Christine, promise to encourage each other professionally, socially, and emotionally? To guide each other, through dark times and bright? And that only one of you will freak out about finances at any given time?
And now for the rings.
Steven, repeat after me. “I give you this ring, as a visible and constant symbol, of our wedding vows. Please don’t remove it, in times of anger, for they are fleeting, and our love is steadfast. With this ring, I thee wed.”
Christine, repeat after me. “I give you this ring, as a visible and constant symbol, of our wedding vows. Please don’t remove it, in times of anger, for they are fleeting, and our love is steadfast. With this ring, I thee wed.”
We also threw in a reference to Princess Bride because, well, I wrote the vows so I could do whatever I wanted. *grins* I think the full vows are in my planning journal, if you want the whole effect...
HTH!