I'd like to recommend a program/website: Anki
Why I'm recommending it is because I have personally found it useful. It's a flash card program. The electronic version of that stack of business-card size cards that you use to memorise facts, figures, vocabulary, etc. The program allows you to create a "deck of cards", front and back. When you revise, it'll show the front to you, and then after you click a button, it'll show the back as well, followed by 4 buttons: again, hard, good, easy.
This system is actually properly developed in the sense that if you click "hard" for a card you're seeing the first time, account (oh ya, you'll have to create an account) will remember it and bring it out to you the next day for you to revise. If you press good, it'll be after 3 days, easy, after 7 days. The second time you encounter it, clicking hard will make it reappear after 3 days, good, after 10 days, and easy, after 20-something days.
By doing so, it helps you memorise the information on the card. Scientists have found out an optimal rate at which we must be exposed to information to be memorised so that we memorise it the best. This is something like 1 day, 3 days, 7 days, and then 1 month or along those lines. I doubt the programmer for Anki did any research, nor did he read up intensively on how many days to put, but there's no specific number of days that are actually needed because it varies from person to person.
The program can be downloaded and installed on to your com for ease of use, but there's also a more limited use "web version" (you can sign in to your account using an internet browser) which is useful for people on the move, or who log in to their computer at work or something. It allows you to revise your cards, add new ones, and edit cards, but that's all. It's good enough though, you can always change the more advanced options at home.
So far, I've been using it to memorise Japanese Kanji. I should be getting pretty close to around 400 now, which helps me immensely with reading, although I'm still a very very long way off from reading complete sentences without finding a word I don't know. It's probably because I learn Kanji all over the place, and not actually follow any specific syllabus like the JLPT or the jouyou kanji (literally: commonly used kanji). I like to think of it as torrenting vs. progressive download. But in this case, I'm at a disadvantage because supposedly I will not be able to take any of the JLPT tests (except 5 possibly) since I don't have the required vocabulary. However, once I've learnt enough, I'll probably be able to skip to like, JLPT 3 or maybe even 2, although that'd be like many years time.
The program has been very useful in expanding my vocabulary, and also for revision. I keep adding new words that I'd like to learn whenever possible, and so this method should suit me. My kanji almost always comes from song lyrics, which makes it easier to remember too.
Keep in mind that this program is not limited to helping you memorise Japanese Kanji, neither is it limited to vocabulary. You can use it in anyway you see fit! Memorise country names, city names, universal constants (speed of light perhaps? 2.998 x 10^8 m/s <-- memorised that a long time ago). Any piece of information you want to drill into your head can be done easily through this software. There are even pre-made decks for you to download (I still prefer to create my own though, since learning is a personal process and works better if customised).
Oh, and did I mention it's free?