DejaVu fonts.
This is a complete family of high-quality fonts with a
huge range of special characters, including IPA.
LaTeX package
TIPA.
If you want to use LaTeX for linguistics purposes,
there are many packages available. Look for the TIPA
package in your distribution.
Example transcriptions
Oxford English
Dictionary. Uses IPA for pronunciation notes.
Probably not available except on campus. Systematically
misuses the /r/ symbol (trill) when it should use /ɹ/.
Wikionary.
Uses IPA for pronunciation. Correctly uses /ɹ/.
Merriam-Webster
Dictionary. It uses an obsolete but widespread system
of almost-English spelling with lots of extra diacritics.
In general, linguists do not use this notation any
more, and you shouldn't either.
Pronunciation
respelling for English. Table of commonly used
spelling systems meant to indicate pronunciation
rather than orthography. This is a way of matching
IPA to other dictionary systems, such as AHD
(American Heritage Dictionary) and MWCF
(Merriam-Webster Collegiate Dictionary).
Interactive
Sagittal Section. This is a side-view cut-away
of the vocal tract. You select any
combination of features, and the diagram changes to
show the position and activity of the vocal tract and
the IPA symbol.