A common myth about Chinese languages is that different Chinese languages can be written with the same characters. This is actually far from true as there are significant differences in grammar, usage and etymology in different Chinese languages.
In May 2007 the Ministry of Education released a list of 300 characters for writing Hoklo Taiwanese. You can download a pdf of the 300 characters and a later list of 400 characters. Pinyin News has some more information. A-gu also discusses some of the new characters here.
Here are a few simple examples that demonstrate the differences between Taiwanese (台語 also known as Minnan 閩南語, Hokkien and Hoklo 福佬) written using Chinese characters (漢字 Hanzi) and standard Chinese.
Have you eaten yet?
standard Chinese: 你吃飽了沒
I have to leave now.
standard Chinese: 我先走了
standard Chinese: 哪裡
standard Chinese: 什麼
standard Chinese: 聽不懂
standard Chinese: 謝謝
standard Chinese: 不一樣
Here are some links to examples of Chinese characters used on signs in Taiwan to specificially represent the Taiwanese language.
The text below comes from a forwarded email. The first example is written in standard Chinese. The next three examples are written in Taiwanese using (1) Chinese characters, (2) a mixture of Chinese characters and romanisation and (3) romanisation. Please note, the romanised version does not include numbers or diacritical marks that are necessary to indicate the tones. Finally there is an English translation of the text.
高雄 - 新加坡 (standard Chinese)
高雄 - 新加坡 (Taiwanese using only Chinese characters)
高雄 - 新加坡 (Taiwanese using a combination of Chinese characters and romanisation)
今仔日ui3高雄坐新加坡航空來新加坡。Ti7機場e5時，飛機慢beh kah一點鐘才到。因為飛機慢到，新加坡航空特別chhoan一koa礦泉水hou7人客lim免錢e5。聽人講新加坡航空e5服務be7 bai2 ，確實，ui3提供礦泉水這件來看，hou7我e5第一印象猶be7 bai2。
Kohiong-Singapore (Taiwanese using romanisation without tone marks or numbers)
Kin-a-jit ui Kohiong che Singapore hangkhong lai Singapore. Ti ki-tiun esi, hui-ki ban beh kah 1 tiamcheng chiah kau. Eng-ui hui-ki ban kau, Singapore hangkhong tekpiat chhoan chit koa khongchoan chui hou langkheh lim bian chin e. Thian lang kong Singapore hangkhong e hokbu be bai, khaksit, ui in the-kiong khongchoan chui chit kian lai khoan, hou goa e te it insiong iau be bai.
Kaohsiung - Singapore (English translation)
Today's Singapore Airlines flight from Singapore to Kaohsiung was about one hour late. Because it was delayed Singapore Airlines served some mineral water for the passengers waiting in Kaohsiung. I had heard Singapore Airlines service was not bad and when they served the mineral water it left me with a good impression.