* "A" as in "ah" (like "ah, I see")
* "E" as in "e" in "pet", or the "ai" in "pain"
* "I" as in the "i" in "pit" or the "ea" in "peat"
* "O" as in the "o" in "cot" or the "o" in "cone"
* "U" as in the "u" in "put" or the "oo" in "doom"
(Americans might notice that this approximately reflects the sounds those letters represent in Spanish)
Exception/refinement: If you know the name is from an Indian language, read "a" as the "u" in "putt"
(Edit: Improved the example given for "a")