I heard that commercial flight logs are publicly available from the FAA, including mechanical delay reasons, etc. Is this true? If so, where can this information be found?
Under the Freedom of Information Act you can request these records from the FAA. Please read more about doing so here: http://www.faa.gov/foia/foia_request/
The data you want is here: http://www.transtats.bts.gov/DL_SelectFields.asp?Table_ID=236&DB_Short_Name=On-Time
Select pre-zipped file to get all fields. You have to download it one month at a time.
I believe Flight Aware allows you to view filed flight plans. It also lets you know where the aircraft is in-flight, although I am not sure how accurate that information is.