Orthography for Hokkien is a bit complicated for a few reasons. The government has mandated a roman writing system, but it is not very popular. This mandate went out in 2008, so it is still new. It is a hard adjustment though. The more popular writing system is to use Chinese characters, but phonetically.  Below is an example of the writing system from the Taiwanese government.

Consonants

Vowels

http://english.moe.gov.tw/public/Attachment/9851214271.pdf