FOREX is the exchange of one currency to another though an internet based platform as well as other prodcuts such as Bullion, options, futures and CFD's
The forex industry is the largest market worldwide, with more than $2 trillion changing hands daily.

As mentioned the forex industry is based online and therefore has no central office like NASDAQ or Dubai Gold exchange, as an example. This gives forex the advantage of being able to operate 24/7 and not being OTC trade is also an advantage over those that are not online like the FTSE.

The online network compromises of Banks and institutional and retail clients.

As it is an online network there is also the issue of Fund Security, so make sure that if you decided to trade. Only choose those companies that are regulated. Different countries have different regulated bodies.

For the US a forex company has to be a member of the NFA and be regulated by the CFTC.
In New Zealand the regulated body is NZX and in Russia its the RFA.

Also as mentioned there are different platforms to cater for different needs. Such as MT4, CurrenX.

Also for the first time ever an OTC Stock Market will offer online trading as well as forex. This has come with the recent partnership of NASDAQ with IKON Global Market. Who will now offer trading in their industry through the online system like forex.

NASDAQ joint the venture with Ikon GM for many reasons - their Cusotmer services and the fact that they offer 25 different platforms to cater for all the customers needs. This is by far more than other forex companies.

http://www.nasdaq.com/newsroom/news/newsroomnewsStory.aspx?textpath=pr2009%5CACQPMZ200910221039PRIMZONEFULLFEED176229.htm

As for the website forexobroker... Personally i had not previously heard of the website. They only seem to give info about forex with no offer or adverts for trading or Demo Accounts.