http://en.wiktionary.org/wiki/sew
sew:
http://dictionary.cambridge.org/dictionary/british/sew
UK /səʊ/ US /soʊ/
so:
http://dictionary.cambridge.org/dictionary/british/so
sue:
http://dictionary.cambridge.org/dictionary/british/sue
/suː/
"So" and "sew" are homophones in both UK and US English.
http://en.wiktionary.org/wiki/sew