How to become a Muslim
Becoming a Muslim is a life-changing experience, but many millions of people the world over have become Muslim (i.e. chosen to accept Islam as their way of life). It's a fairly easy process. Here is a basic guide for how to become Muslim.
Preconditions
Before becoming Muslim, make sure that you think it's the truth, that you think Islam is what it claims to be. Make sure that you want to be Muslim for the rest of your life. The point may being end up being moot for you, but Muslims believe that there is greater punishment to be received for being Muslim and then revoking it than not becoming Muslim. So be sure.
There are plenty of Muslims on the planet, and while Muslims become overjoyed at hearing another person has chosen to submit to God, we are not interested in forcing you to become Muslim. The Qur'an says (well, translated into English) in Chapter 2, Ayah 256:
Let there be no compulsion in religion: Truth stands out clear from error: whoever rejects falsehoood and believes in Good has grasped the most trustworthy handhold, that never breaks.
The core issue should be the truth or falsity of Islam, not on whether you feel it would be difficult or inconvenient to be Muslim. If it's the truth, then the hardship is incidental, and just something that has to be dealt with. Just as you would have to accept it if someone told you that they didn't love you when you hoped that they would; there's no point denying the truth because it's uncomfortable.
It's important to understand Islam to get information from authentic sources. There's a lot of misinformation and misconceptions about Islam out there. A good place to start is reading books/websites about Islam by Muslims. There's no need to restrict yourself to these sources, but they should be part of your study.
If you have a question about Islam that you haven't got a satisfactory answer from the books on, you can ask a Muslim like me.
Necessary acts
Once you've decided to become Muslim and you're sure it's the right thing to do, then the requirements to become Muslim are easy. You say the following:
"I declare that there is no God but The One God (Allah), and that Muhammad is His messenger."
This is called the "Declaration of Faith". Provided that you said it with full conviction and understanding of its consequences, and without duress you are now Muslim. Congratulations.
Note that the above has deep consequences. It means that you must follow the Qur'an and Muhammad's teachings, which are basically an elaboration of the Qur'an. This includes spiritual and practical aspects of Islam.
Preferred acts
The above is what is necessary, but there are several additional things that it is preferred if they are done. Firstly, it is preferred if the Declaration of Faith is also made in Arabic. Roughly transliterated into English, this reads: "Ash-hadu anna laa ilaaha illa Allah, wa ash-hadu anna Muhammadan rasool Allah". Secondly, it is preferred if this is done in the presence of two Muslim witnesses. This will provide an opportunity for you to "connect" with the Muslim community. Thirdly, after becoming Muslim, it is good to have a shower with the intention of purifying the body for religious purposes. This is called ghusl. Fourthly, if your name is inappropriate; say for example, your name was Zeus or Diana* (Roman gods), then it is highly recommended to change your name -- but only if it is a name inappropriate for a Muslim to have.
*: You might think that it is quite uncommon for women to become Muslim because of the misconception that Islam oppresses women. However, anecdotal evidence suggests that for every man who becomes Muslim, two women become Muslim.