They usually use the same pronounce of chinese characters to write. Any the same pronounce of chinese character can be used. Perhaps depends on what is the first coming up when you type pinyin or zhuyin. It is like what cantonese does.

True, it doesn't. OK, actually it has some specific characters (like [人因]  in1 and [勿会] bue7), but for centuries there was no official standard for the colloquial and whether the new TW standard characters will prevail still remains to be seen (case in point: I cannot even post them in this forum, the browser says "emoji" when I try to paste them in ... [XY] means - left hand side of the character is X, right hand side is Y, but the font doesn't have it as a single character :-(.

That does not mean we should give up on trying to write it, though ... if you don't write the language down, it cannot be preserved properly. And as for POJ only or mixed characters/romanization systems ... I don't know, "你明a日beh去toloh?" just looks bo saN bo sì (无三无四) to me. I would go with 汝明仔日欲去佗 (the TW system), even though many native speakers will at first give you a tiaN bo (听无） kind-a look.

Now, I recognize this is an old thread, but since this question may come up again (and most posts in this forum are about Taiwanese Mandarin and not 台语 / Minnan), here is my recommendation: check out the links posted by Ekiak above, as well as Lin's Taiwanese grammar, the apple iphone 萌典 (where available) - a lot has happened over the last 10 years in trying to make Hokkien a written language, so I guess it is up to everybody if we want to make it happen.

There is actually a Chinese characters writing System for Hokkien,we call it 正字. Here is some online dictionaris.

http://www.edutech.org.tw/DICT/All-Dictionaries.htm

http://twblg.dict.edu.tw/holodict_new/default.jsp

If you can read Chinese,this site is even better.A lot of member in this Chinese forum are Hokkien who can write Hokkien Chinese characters.

http://tieba.baidu.com/f?kw=闽南语&fr=index&fp=0&ie=utf-8

The language has no words.