Whoa, take it easy, folks.
We definitely do need more people. All detailed information you need is here
. Basically, yes, the easiest way is to find the scene you want to tackle, click "edit", type in your translation, "alt-enter" to go to the next line, and so on (you won't be able to modify the original Japanese text, so don't worry about that). Keep the tags (just copy them, don't try to translate filenames and code) and try to follow the guidelines in the link above.
About half of the content in there is "verified" (green checkmarks
) - that is, I've finished editing it myself and considered it "good enough". If you still find mistakes within that, please let me know (trying to edit it right there won't work). The other half - indeed, full of mistakes and inaccuracies - can be edited with no restrictions. If you really don't want to do it online, you can download the file (see the icon next to each scene), edit it and send it to me.
The wiki has more info, but that's the gist of it. Let me know if you have any other questions (if you're lucky, might even catch me on #tlwiki).