My favorite is ARC246 by BuTel. It allows a automatic download of any or all frequencies in your county and state from this site, and sets up trunking TGID's & para's(this is a big help). It is $40, but well worth it. It has a neat virtual control panel that works your scanner from the keyboard., but the best part is that it logs all the information(freq & PL) and lets you see your scanner window in a much larger scale that you can actually see clearly. The logging is great when searching, but it is also handy for normal scanning. Often, I do not look up in time to see what agency was just talking, so I just look at the log. See the the examples on their web site
http://www.butelsoftware.com/ You can download it on a free trial basis to see if you like it. There are also free programs, such as
FreeSCAN, that do the same thing.