Generally you'd do these two tasks in the other order:
- Do part-of-speech tagging
- Run a parser using the POS tags as input
OpenNLP's documentation isn't that thorough and some of it's gotten hard to find due to the switch to apache. Some (potentially slightly out-of-date) tutorials are available in the old SF wiki.
You might want to take a look at the Stanford NLP tools, in particular the Stanford POS Tagger and the Stanford Parser. Both have downloads that include pre-trained model files and they also have demo files in the top-level directory that show how to get started with the API and short shell scripts that show how to use the tools from the command-line.
LingPipe might be another good toolkit to check out. A quick search here will lead you to a number of similar questions with links to other alternatives, too!
