First of all, you need to learn the basic scripts (hiragana and katakana), and find yourself a beginner's textbook that you can use in addition to the content on this site.
From there, it really depends on your aims. You'll need to focus your learning on your needs. If you're learning just out of interest, however, then you can plan a more long-term approach that will suit your learning style and ultimately help you gain fluency a lot quicker.
Kanji is the obstacle most people make a big deal out of, but it really depends on your approach. You need to know roughly between 2000-3000 eventually, but you can see their relative importance by looking at the statistics from a study of kanji used throughout wikipedia:
173 kanji cover 50%.
454 kanji cover 75%.
874 kanji cover 90%
1214 kanji cover 95%
2061 kanji cover 99%
2456 kanji cover 99.5%
3489 kanji cover 99.9%
I recommend Heisig's Remembering the Kanji. You can learn how to write/recognise over 2000 within 3-6 months, and it gives you security in actually remembering them. Recently a small set based on the above statistics has been organised containing around 1100 characters (RTK Lite). You can save yourself time by sticking to this set, and learn the others afterwards or as and when you feel you're ready. You might want to ask more questions at this forum
http://forum.koohii.com/ since I haven't used RTK Lite myself.
After you can recognise these characters, you can start reviewing sentences which will teach you how to read them while learning vocabulary. There are premade decks available online with audio to get you started quickly.
http://ichi2.net/anki/ (download and check the shared decks)
http://forum.koohii.com/viewtopic.php?id=2548
http://smart.fm (check core 2000/6000 decks)
I really recommend Anki since it's more flexible and portable. Either way, using some form of SRS-based learning tool works wonders even if your memory isn't particularly great (much like Heisig). You'll find premade spreadsheets for higher-level grammar as and when you need them, too.
You also need to expose yourself to as much real language as you can through TV shows, radio, reading, etc, and get as much practice using the language as you can. If you're a complete beginner, JPod will help you with this until your comprehension skills are ready for tackling the "outside (Japanese) world". You also have a lot of time to think about what methods you want to use, so don't let all the information overwhelm you.