Hail Dawn, goddess of many names!
Éostre (Old English, West Saxon dialect) AY-aw-streh (ay as in say, aw as in awe)
Éastre (Old English, Northumbrian dialect). AY-ah-streh (ay as in say)
Both forms are used by contemporary pagans. Occasionally—probably under the influence of Ostara—written Oestre. (Technically, this form is historically incorrect, if you care about such things.)
*Ôstarâ (Old High German) OH-sta-ra (but most English-speakers say oh-STAR-a; technically, this is historically incorrect, if you care about such things.)
Name reconstructed by the Brothers Grimm. Probably the most frequently-used name for the goddess, and her springtime festival, among contemporary pagans and heathens.