Impressive, I like the colors ! 

 It wasn't supposed to be perfect. I works, that's all I wanted.

If you think you can do better, then do it, you've got my sprites here : http://akwanet.servhome.org/PARTAGE/PA/android_sprites.png

 @DrawBringer : thanks a lot ! I'm going to use my Amiga again and make it my pixel art machine !

I think it would be good if I upgrade it with a CompactFlash drive :)

 @DrawBringer: because I'm not an Amiga user, and I don't know well the software available on this platform. I bought this Amiga in 2007 or 2008. It works well but I only use it for some old video games such as Project-X, Turrican II, Lemmings... etc

Anyway, if you have some suggestion about wich software to use to make pixel art easily then export it to a PC running Ubuntu or Windows, tell me =)

 I don't see any window that looks open. I drawed this one as how it is in reality :)

A colored version ? Why not... I'll post it as soon as I can if you want.

The windows on the sides of the building have a balcony, but it is very small, that's why it looks like a grid and yes this is not made for someone to stand on them.

Thanks for your comment ! :)

(sorry if my english is not very good, I'm french)