Mos Eisley (pronounced /mɑs aɪzliː/, moss izelee,
And here's a sound clip of the pronunciation, also from Wookieepedia.
To me it sounds more like 'moss i-sszlee'
As for how a native Tatooian pronounces it, listen to Watto which confirms it is 'moss i-sszleee'.
Just for some background, the same Wookieepedia site describes it as being:
located in a valley somewhere to the southeast of the Jundland Wastes and roughly 80 kilometers north of Anchorhead, near the desert palace of Jabba the Hutt.
and Lando Calrissian is supposed to have said:
"Mos Eisley is known as the galaxy's armpit. I guess there are worse parts of the anatomy where we could be stuck."
It was mentioned in Episode II: Attack of the Clones and seen in A New Hope.
Nothing can compare with the real Mos Eisley though ;-)