There are two kinds of generators, the random kind and the non-random kind. Rum + Monkey has one of the random ones, the Na'vi Name Generator; type in a name like "Paul," enter your gender (Tutean = male while Tutee = female), and the will of Eywa generates the appropriately AVATAR-ish name Tsyal. But the name is linked to its meaning; "Paul" means "small" and if you enter "small," you get Tsyal as well. (See the BabyNameAddicts site to figure out your name's meaning.)
The names are definitely Na'vi-sounding but the assignments are fairly random, rather than Pig Latin plays on people's names; witness that "Obama" becomes Bakteyo and "Bush" becomes Tzmukan. Exception: "Cameron" becomes Taronyu (that's "hunter" to us English-speakers).
This name generator wasn't good enough for Omatikaya, a.k.a. artist Carolyn Rogers, who created the Better Na'vi Name Generator. (It's also hosted on Rum + Monkey—that's the business R+M is in, they're the name-generator generator.) Now when you type in "Paul" you get Aka'ula, which is cooler-sounding if only because it has an exotic-sounding glottal stop.
Neither of these name generators gels yet with the Concise Na'vi Dictionary (PDF here) at Learn Na'vi, which seems pretty authoritative considering they're pushing a Learn Na'vi app. For instance, look up hufwe (Na'vi for wind) in the dictionary, enter "wind" in either name generator above, and you get back either Wor'itan or Adhiguna.
The bottom line is that these are great idea generators without necessarily being ready to translate at a United Nations level of accuracy. Have fun!
What's your Na'vi name and how did you find it?