If you have a Western Digital Hard Drive on your home network and you want to watch movies and listen to music that you have saved on it, I found the app that works great on my Ipads and Iphone 4s.
OPlayer HD (the one that you pay for) allows me to play movies and listen to music without the need to download or convert the file. If you use OPlayer HD Lite (the free version), the movies will play in a mirrored view (printed words will be from right to left) and if you can tolerate that, stay with the free version.
To navigate to your network HD, simply"
1. open the app
2. tap on the globe in the left hand column
3. type in the IP address of your HD on your network
a. if you have the paid for version, you can book mark the address at this time (the free version will not keep your bookmark after you close the app)
b. my IP address was 192.168.1.27:9000. The ":9000" sent me to Twonkymedia provided with my HD software which allows me to select Music, Photos, and Videos.
c. Once I have selected my file, a window comes up to ask me if I want to play the file or download the file. This is exceptionally useful as I can connect my Ipad to my car's video system.
I hope this has helped you on the issue.