Can you yell me if the following sentence is correct:
I'm in england
Watashi wa Igirisu ni iru
Watashi wa Igirisu ni desu

I don't understand the difference between "iru" and "desu", both are translated as to be.

Question

Can you yell me if the following sentence is correct:
I'm in england
Watashi wa Igirisu ni iru
Watashi wa Igirisu ni desu

I don't understand the difference between "iru" and "desu", both are translated as to be.

Answer

In this case, "Watashi wa Igirisu ni iru." is correct.

"desu": 
 "A is B." means "A = B".
 So, it is translated into "A wa B desu."
 If above sentence is "I am England.", it is translated into "Watashi ha Igirisu desu."
 (of course strange.)

"iru":
 "iru" is near meaning of "stay" or "exist".

Answer

yes, the correct one is watashi wa igirisu ni iru 私はイギリスにいる。 or watashi wa igirisu ni imasu.　私はイギリスにいます。
as Takashi says iru / いる means exist. if you want to say "I'm England" that would be watashi wa igirisu desu.

Answer

Watashi wa Igirisu ni iru...RIGHT
Watashi wa Igirisu ni desu...WRONG.

Answer

Don't trust the translation too much between Japanese and English/French whatever. Our grammar is so different that there's some words we don't have in  common such as "desu"!

Wwatashi wa igirisu ni iru 
is correct!