Hactar can play both go and capture go. Capture go is easier game for the computer, so Hactar can play it against you without a server. Hactar plays go using a server, this way Hactar has decent strength in go (Note: Hactar Lite plays at beginner level.) You can find more information from <a href="http://gowrite.net/hactar/client.php?lang=en">Hactar home pages</a>.
Differences between Hactar Go full version and Hactar Go Lite: 1. The full version has a go opponent for 13x13 and 19x19 boards (subscription in Lite). 2. The full version has internet game search (subscription in Lite). 3. The full version offers more accurate AI analysis. Both versions offer even more accurate AI as subscription.
Internet has a lot of go related material. Some of the best knows links are collected in <a href="http://gowrite.net/hactar/client.php?lang=en&topic=links">Hactar links</a>.