http://www.ntat.gov.tw/county/ntat_ch/ntat_en/ab26_online.jsp
To inquire about your taxes online, for foreign residents of Taipei City (not county)
Service hotline (02) 2311-3711 ext. 1116 on weekdays between 8:30 a.m. and 5:30 p.m.
More info at: http://www.chinapost.com.tw/taiwan/local/taipei/2009/04/15/204253/New-online.htm