Starting with ABC

Like in every language, the first thing you should do, is to learn the alphabet. I was surprised to find out that the Japanese have two alphabets. One is Hiragana ( ひらがな) and the other is Katakana (カタカナ). I won't start to talk about Kanji in this post because it's a subject by itself.
Hiragana is the alphabet for the Japanese words and Katakana is for the foreign words they adopted from other languages. Why they needed different alphabet for the foreign words? I have no idea.
Anyway, the two alphabets are containing 46 syllables:

Hiragana:

Katakana:

Also there are extended syllables chart containing 25 syllables:

And if it wasn't enough, there is a third chart with 34 syllables. this chart is of modified syllables containing small ya (ゃ), yu (ゅ), yo (ょ):

Well, no wonder people are giving up even before they have started. But the secret is, that the alphabet (including Kanji) is the hardest part. Japanese grammar is relatively easy (or so they say).


Tip
It is important to become used to write the Kana in the right order. when you'll get to Kanji, you'll understand.
Tip
The syllable ヲ (wo) is not used.


More about Kana
To know how to read every word written in Kana you need to be familiar with some rules.
Hiragana:

• Long Vowels: accomplished easily by dabbling the vowel: ああ, いい, うう, ええ, おお
• Long Vowels in syllables: the same except the お column (お こ そ と の ほ も よ ろ ご ぞ ど ぼ ぽ). In that column the long sound of "o" is written with う So all the row of "K" will be: かあ (kaa), きい (kii), くう (kuu), けえ (kee), こう (koo). The exception to that rule are the verbs. In verbs the ending read as it written: おう (to chase) is read "ou".
• Double Consonants: to dabble the consonant, you should add little tsu (っ) before it.
• Special partials: when は (ha) marks the topic of a sentence, it pronounced as "wa". When へ (he) marks the direction of movement, it pronounced as "e". Then を (wo) marks the object of a verb, it pronounced as "o".

Katakana:

• Long Vowels: accomplished easily by adding ー after the vowel: アー, イー, ウー, エー, オー
• Double Consonants: to dabble the consonant, you should add little tsu (ッ) before it.
• To fit other languages: there are some combinations with little ァ, ィ, ゥ, ェ, ォ to match the other languages:
• ティ "ti", トゥ "tu"
• ディ "di", ドゥ "du"
• ファ "fa", フィ "fi", フェ "fe", フォ "fo" 
• ウィ "wi", ウェ "we", ウォ "wo"
• ヴァ "va", ヴィ "vi", ヴ "vu", ヴェ "ve", ヴォ "vo"
• ジェ "je", シェ "she", チェ "che"

Aside from Hiragana and Katakana you'll get by a term Romaji. It is the writing of Japanese phonetic characters as Roman letters. But don't jump from joy, they are almost never used, and I'll recommend you not to loose your time with it.

Some History
The Japanese alphabet came from the Chinese Kanji. Take a look at the morphing symbols: