The below text is now luckily obsolete. After almost half a year, Nikon finally fixed their applications so they can run with Snow Leopard.
If you launch ViewNX 1.4 under Mac OS X 10.6 (Snow Leopard), all text labels may be replaced by strange strings like IDS_MENU_FILE and a lot of other strings beginning with IDS. There are apparently problems with Capture NX 2 as well.
Your system is fine. The problem is with the software itself, and we have to wait for an update from Nikon.
There is a web page from Nikon that clarifies the situation. It is not very flattering for Nikon.
The page explains what Nikon planned to start with. Capture NX 1 is not part of the software that was supposed to work, and they will not do anything to make it work in the future. Nikon has pretty much abandoned Capture NX 1, so those of us who buy new cameras, like the D5000, have to upgrade to Capture NX 2, which does not work with Snow Leopard, which... Well, the situation is not ideal.