For those whose Latin and Greek is as bad as mine or worse, here are some online language tools (or cheats!) I find useful.
Words by William Whitaker allows you to submit entire Latin phrases, and it translates each word to English, giving all possible parsing. Quite useful for reading those theological writings which have Latin quotes untranslated :-)
The Perseus Digital Library has heaps of useful tools and resources, and I particularly use it for Greek, though it also has Latin resources and more. The tools I use the most would be the Dictionary Headword Lookup (search for all dictionary entries which contain a certain string of letters) and even more the Greek Morphological Analysis (after submitting a word, generates possible morphological analyses and links to related dictionary entries). Amongst other things, the Library also allows you to look up all occurrences of words within the many texts stored in the database.
While I'm at it, another site I only recently found out about is http://www.zhubert.com/, a site by Zack Hubert, whose Bible Page has many useful tools, including hypertext information on parsing etc when you hover over words in the Greek text (works for LXX as well as GNT!). While you can also display Hebrew text, I think the Hebrew side of things is still much more a work in progress, and more underdeveloped than the Greek. But go and check it out for yourself!