That would depend on how you're using it... present tense? Past tense? Future tense? Conditional?

The most common are:
present - yo voy; pronounced "Yoh boy" (I go, I do go, I am going)
preterit - yo fui; pronounced "Yoh fwee" (I went, I did go)
imperfect - yo iba; pronounced "Yoh eebah" (I was going, I used to go)
future - Yo iré; pronounced "Yoh eeray" (I will go)

I forgot to include these the first time, because they are less commonly used unless you're an advanced Spanish-speaker:
Yo he ido; pronounced "Yoh eh eedoh" (I have gone)
Yo iría; pronounced "Yo eereeyah" (I would go)
Yo habría ido; pronounced "Yo abriyah eedoh" (I would have gone)