Here are some Latin resources I have found helpful.
Lewis, C.T., C . Short, A Latin Dictionary, Oxford UP, Oxford – New York 1879, reprinted 1995.
This is available online at the Perseus project, and through the University of Chicago.
There one can also find a parsing tool.
Diogenes contains the Lewis and Short Dictionary and may be downloaded. It includes a parsing tool. It also has a Greek component.
Smith, W., T.D. Hall, A Copius and Critical English-Latin Dictionary to which is added a Dictionary of Proper Names, Harper & Brothers, 1871.
Gildersleeve, B.L., G. Lodge, Gildersleeve’s Latin Grammar, Bolchazy-Carducci, Wauconda IL 2003, reprint of 31895.
This is available for online viewing and download.
Döderlein, Ludwig von, Döderlein’s Hand-book of Latin Synonymes, tr. H.H. Arnold, intro. S.H. Taylor, W.F. Draper, Andover MA 1858.
Küehner, R., C. Stegmann, Ausführliche Grammatik der Lateinischen Sprache, 2 vol., Hahnsche Buchhandlung, Hannover, 1912-14. Vol. 1, R. Kuehner, Elementar-, Formen– und Wortlehre, 2d ed. rev. F. Holzweissig, 1912; vol. 2, R. Küehner – C. Stegmann, Satzlehre, 2d ed. 1914. 5th ed. rev. by A. Thierfelder, 1976
The Correspondence of M. Tullius Cicero, ed. R.Y. Tyrrell – L.C. Purser, Dublin – London 1904-1933, repr. Georg Olms 1969.
English translations are available at the Perseus Project.
Links to other Latin Resources
Tufts University Department of Classics has a useful page of resources.
Harvard University Department of Classics has numerous online resources.
Notre Dame University, Indiana, has a number of resources.
Other sites will be linked here as I become aware of them.