What's the difference between Spanish spoken in Spain and Mexico?

I want to learn Spanish, just for talking with people from Latin America (mainly to talk to Mexica)

spanish is for spain and south america obtained his own language few centuries ago from mixed peoples like slaves, and another incas.

Both are almost the same, except the accent and some words.

LIES!
i speak spanish , i live on the border to mexico.
so i speak regular spanish. and spain speaks Castilian spanish, which has different pronunciations and is a little bit more proper.

Spanish has it's dialects like the US has "southern," "midwestern," "northeastern," ..etc. Spoken spanish is also known as "el castellano".....aka "spanish." However, due to local indigenous influences....new words are added. Spanish has been controlled by the "Royal Spanish Academy" for years as to what is proper....however, in the last couple of decades, it has had to recognize many colloquial additions and in fact has accepted many "mexicanísmos" in it's dictionary (too many to list).

I was taught in a linguistics class that amongst educated spanish speakers, there is much less difficulty understanding each other than say a northeasterner talking with a southerner.....much less linguistic variation used. A few years ago a dictionary called the "Diccionario Panhispánico de Dudas" was printed that was the result of a long project to resolve different meanings of many words common to most of the hispanic countries. Each country has it's own "Royal Academy" of language and they came together to resolve those linguistical issues.

Mexican spanish of course as stated has many indigenous influences.....words like..escuincle, achinchincle, zopilote, aguacate.....and tons of others too.

In addition to the various answers people have left here, I would just like to inform you that when there are multiple forms of the same language, it's known as dialects. Here in the U.S. we have a different dialect of English than people do in England.

I HAVE A FRIEND WHO WAS BORN IN "SPANISH" Los Angles, CALIFORNIA, U.S.A. HE SAYS THE SPANISH HE GREW UP WITH IS SIMULAR TO THE SPANISH THEY SPEAK IN MEXICO CITY. THE PRONOUNCMENTS OF SOME WORDS ARE DIFFERENT........THE SPANISH THEY SPEAK IN THE CENTRAL PART OF U.S.A. ARE DIFFERENT EVEN MORE THAN IS SPOKEN IN MEXICO CITY! HE SAYS, IT'S LIKE A SLANG OR A DRAWL ON SOME WORDS, JUST ENOUGH TO KEEP YOU CONFUSED IN LISTENING TO A CONVERSATION.