Itunes and a grey Playlist

Do you use your iPod with another computer?

Sounds like your iPod is set for automatic update, in that mode the songs are greyed out and inaccessible. A lock symbol at the bottom of the screen also means that you are in the 'Automatic' update mode
The iPod offers three ways to transfer music from your computer. You can select one of the following update modes from the iPod Preferences menu in iTunes (Edit=>Preferences=>'iPod' tab):
1) Automatically update all songs and playlists. This is the default mode, in which your entire music library, including playlists, is automatically synced to your iPod. If the music library on your computer exceeds the iPod storage capacity, you are prompted to select a different update method.
2) Automatically update selected playlists only. With this option, iTunes automatically copies the playlists you have selected to the iPod when you connect it to the computer.
3) Manually manage songs and playlists. You can also choose to transfer music to the iPod manually. This allows you to drag and drop individual songs and playlists from iTunes to the iPod.