If such a thing exists, can someone please direct me to a good online dictionary that shows the inflected forms of words (e.g. hanashi, hanashita, hanashiteiru, etc.), especially verbs?

I'm not sure that exists -- EDICT will do reverse conjugation (that is, if you put in 行けば it will attempt to tell you what conjugation that is), but I think the conjugation system in Japanese is simple enough that most dictionaries don't consider it worthwhile. There's only 2 irregular verbs and a handful of irregular forms in a few verbs, and outside of that there's only 2 major classes of verbs. It is true that -u verbs have some complexity with the -te and past forms.

All you really need is a list that shows the conjugation of one verb for each type, and then you can apply that to every other verb.

(incidentally, "hanashiteiru" is not an inflected form, it's the -te form "hanashite" plus the verb "iru".)

I'm not sure if this is what you mean, but I've used this

http://homepage3.nifty.com/jgrammar/gram.../index.htm

If you click on the [V] link for a verb in WWWJDIC you get a big conjugation table for it (and it has the advantage over oregum's link that you don't have to tell it which class of verb it is).

@oregum and pm215: thanks! Those links are exactly what I'm looking for.

@yudantaiteki: yes, it's true that the conjugation system in Japanese is simple and has few irregular verbs and verb forms. However, I've noticed that I've been confusing conjugations both while reading and speaking. Therefore, I think it'll be helpful for me to see the conjugations for each word when I look them up. Doing so should help solidify my understanding of conjugations more efficiently and allow me to read and speak more smoothly.