In my opinion, Tae Kim's Guide to Japanese (www.guidetojapanese.org) is the best free resource available on the entire internet. It is significantly better than many paid resources I've come across, too. The complete guide is very comprehensive and I kept a printout of the grammar guide by my side all through university.

Hey Celeste, I suggest starting to learn Kana and some basic grammar. I recommend みんなのにほんご, it's a great book which teaches you basic grammar and walks you step by step. There's also kira sensei on youtube that uses the same book but it's in spanish, I hope you can keep up with his spanish but his Japanese is great. Once you have the basics you should learn Kanjis, I recommend the Heisig method but I think everyone has its own way. I hope this helps!

If you're looking for a textbook, Genki I and Genki II are good textbooks I used in class. They also have workbooks and CDs to help you practice. However for free resources I would definitely also recommend Tae Kim's guide as it goes into more detail about the grammar structures and uses.

Since you are bilingual, I'd like you to take a look at my notebook entry. http://www.italki.com/entry/460991 There are more sites I'd like to recommend. http://www.nhk.or.jp/lesson/english/ http://study.u-biq.org/english.html. I hope you can find the best ones for you. ¡Mucha suerte!

I'd most certainly sure recommend Minna no Nihongo. I'm using that book parallel to my lessons :3