When I start to install LW on my Mac it displays a blank window with a pull-down that lets me choose from a dozen languages and an OK button. I figure that either:
1) It's just asking me what language I want to use. If this is the case, it should say so.
2) It's asking me to agree to some unspecified terms.

What's the deal?

It sounds as though you've dwnlded the international version. Just select your language & continue. The blank window sounds a bit mysterious. Which OS version are u using? Before u install LW, ensure u have the most recent Java version installed for your OS version (this is very important.) For mac osx use your softw update (found in System prefs.) And for OS9 see MRJ 2.2.6 for OS 9.2.2: http://docs.info.apple.com/article.html?artnum=120209
MRJ 2.2.5 for OS 8.1-9.2: http://docs.info.apple.com/article.html?artnum=75097

Are u sure you dwnlded LW from the official LW website: http://www.limewire.com/english/content/home.shtml & the dwnld page can be found here: http://www.limewire.com/english/content/download.shtml There is a language selector for the official web site if english is not your language.