You can download IA Vocaloid songs from Nicosound. This site is basically the audio version of NicoNicoDouga. On this site you can download all of IA's songs that have been posted on NicoNicoDouga.
IA's male version is IO.
On the internet. Use 'Youtube to Mp3' converter and convert any song on youtube you like (i.e. any vocaloid song on youtube) so there you go :)
mediafire
You can't get Vocaloid for free, but there is a programme called UTAU which is nearly the same thing; you can also make your own Vocaloids on that.
As of this post 8 Aug, 2012, at a minimum, there are over 120,000 songs using Vocaloid. On the Japanese website, Nico Nico Douga (the central hub of Vocaloid music and videos), we get these numbers: 1. 84,000+ original songs tagged with "Vocaloid" and "オリジナル曲" (original_song). 2. 47,000+ cover songs tagged with "Vocaloid" and "カバー曲" (cover_song). Take the above 120,000+ songs from that website alone and consider the following: 1. Add all the potential Nico Nico Douga videos that were tagged incorrectly. 2. Add any original songs and covers from YouTube that are not reprints of existing videos. 3. All other websites that have original music and covers using Vocaloid. The number is possibly much higher than 120,000.
Yes, Ai is a vocaloid. A vocaloid 3 to be exact.
IA's male version is IO.
On the internet. Use 'Youtube to Mp3' converter and convert any song on youtube you like (i.e. any vocaloid song on youtube) so there you go :)
mediafire
Vocaloid is a program used to simulate a human voice for use in songs. Hatsune Miku is a popular Japanese Vocaloid.
YouTube to MP4 Downloaders work (but it does depend if the song is copyrighted, 'cause if they are then downloading them with a YouTube to MP4 Downloader is illegal).
You can either Google "Vocaloid Download" or "Hatsune Miku program download" That's how I found it. But yeah, It's called Vocaloid: Project Diva.
Yes, it is possible.
There is an entire website dedicated into making stepmania files with Vocaloid songs, you can check it out here: http://vocamania.net/index/ They have made a total of 10 packs with a total of 360 songs stepped (which to me is already a giant collection) an you can also request your songs there! There are also several people in youtube making their own files and sharing it for download. :) http://7mai.blog71.fc2.com/ is also a giant library of vocaloid files for stepmania, but mind the japanese, hahahahaha.
From the internet (I don't suggest this) or buy it in Japan
You have to buy it to have an activation number.
I believe so. If a vocaloid song is fanmade, then i think so. A vocaloid singing a previously-copywrited song, though... I'm not sure, it's probably illegal.