Are there any free, online Portuguese dictionaries (more complete than wikcionário) which provide IPA transcriptions?
If you are looking for the phonetic transcriptions look no further:
If you are on linux, you could also use espeak to generate a transcription (not exactly IPA, but useful):
And as @Flimzy pointed out, espeak does generate IPA with the
--ipa option. Even though it is far from precise, it is still useful if your goal is improving your pronunciation.
Note: Please be more specific with your question. For example, explain why you need a phonetic dictionary that is online (and, probably, accessible through a browser), explain why the resources you have found do not suit your needs. Being more specific will help other people trying to help you, avoid trial-and-error answers (like this one) and simply make the board better.
I also found this research project where they created a pronunciation dictionary for Brazilian Portuguese (São Paulo City dialect). You can download the result as an Excel sheet. However, I can't judge its accuracy.