So you want to get involved in the foreign exchange market, or forex. You’re itching to trade one currency for another and make some profit. But you can’t just barge into Citigroup of Merrill Lynch and start throwing euros and yen around. To participate, you need a forex broker.

The preeminent forex broker for day traders (i.e., average Joes) is Advanced Currency Markets, or ACM. To many people, the Swiss company, founded in 2002, is synonymous with “forex broker,” trading about $70 billion a month.

There are dozens of other brokers, though, who service day traders. It’s done almost exclusively online, and in fact ordinary citizens rarely got involved with forex trading at all until the computer boom of the 1980s, and then exponentially more with the advent of the Internet in the 1990s. Since then, forex brokers have proliferated.

As you might expect, levels of reliability and competence vary from one broker to another. The Internet is rife with unsavory types seeking to take advantage of suckers, so you would do well to investigate thoroughly any broker you’re planning to use. Does their Web site look professional and reassuring, or is it riddled with dead links and spelling errors? Google the broker to see if they’ve been mentioned in news articles. Ask about their track record. And above all, avoid anyone who promises things that sound too good to be true, or who downplay the financial risk involved in forex trading.

Look for a broker that seems to genuinely want your business. Does the firm have customer service representatives available? Is there a phone number you can call to speak to a live person? The Web site should explain things clearly. If the site is full of language that seems designed to go over your head, look for a different broker.

If you set up an account with an online forex broker, it will work like this. First, you must apply for an account, which most brokers allow you to do online. This is to verify your identity and the validity of your bank accounts and financial records. Some brokers also require you to download their forex trading software, while others let you use whatever software you prefer. You will also have to transfer a minimum deposit to your account with your new broker. The minimum can be anywhere from $100 to $2,500.

Ideally, the broker you choose should offer service and support when you need it but should mostly simply stay out of the way and let you conduct your business. If you can find a forex broker who is professional and helpful, your experience in the forex market should be full of smooth sailing.