Depending on the amount of hair, color and texture of hair and how important it is to you to be rid of it, you actually have a couple of options for permanent removal.
Laser can be only legally claim to provide permanent reduction. Electrolysis, if treated by a competent practitioner, can be permanent. If you have the time to educate yourself on the types of lasers used, check out the
http://www.hairtell.com/forum/ubbthreads.php . There are folks on there who can give you some good advice if you don't mind wading through the posts.
Things that pop into my head that I would consider are: Is your hair coarse and dark enough to get a good reduction with laser? If so, what is your skin type? That would be a consideration for the type of laser used. (Also, having laser done before you do any tanning is preferable.) Not paying for a series of treatments, not being bullied into coming in for follow up treatments until you have enough hair to warrant the expense. (Hair grows in cycles, you will not get them all in one treatment. Dormant follicles will need to be treated when they become active.) You are totally in the drivers seat with laser if you educate yourself before hand. The bikini area is not an area that is known to have laser induced regrowth, unlike a woman's face which is a consideration. If you have only a little bit of hair to remove, in an area with a tendency to have ingrown hairs, you could go straight to electrolysis, which can remove all hair regardless of texture or color. Some people also use it to catch the random hairs that pop up after laser treatment.
The key to success with electrolysis is finding a great practitioner!! Preferably one who only does electrolysis. Some businesses advertise electrolysis but then try to talk you into laser once you get to your appointment. They are out there and you can usually go for a consultation and sample treatment, many times at no charge. Shop around. Many laser places are chains, but they can sometimes negotiate a reduced rate. Most electrologists are self employed and aren't willing to haggle much, but they ARE business people and if you have something of value, such as marketing or internet skills they need, they can be very open to bartering. :)