Thank you for the welcome,
Actually my boyfriend is American and he is on a tier 4 visa. I am currently working and studying "Occupation Therapy" in the US. He wants me to relocated to the UK but I am not sure if we should get marry in the US OR UK, or should I go on a student Visa.
Ah, okay, well marrying in the US will be the easiest option, because you would need a visa to marry in the UK (a Marriage Visitor Visa) and then you would have to return to the US to apply for a dependent visa to join him. Once you are married, you could apply for a Tier 4 dependent student visa to join him in the UK. To get the visa you would need to show that you have at least £400 per month to live off for the length of the visa (on top of all the money he had to show for his tuition and living costs during his studies).
Alternatively, as you mentioned, you could get your own Tier 4 student visa, which means you could just move over on your own merits. However, depending on what you would be studying, it may not be easy to find a course that would enable you to move around December time... many university courses will only allow you to start in the Fall because you have to register for an entire year at a time and some classes are two semesters long so you can't start a course in the middle, and you might have to wait until Fall 2011 to move as a student.