You didn't say if you were looking for styles, midi files, whatever ... but here are some midi sites: http://translate.google.com/translate?hl=en&sl=es&u=http://www.educa.rcanaria.es/Usr/Apdorta/cristal/cristal.html&prev=/search%3Fq%3DTango%2Bmidi%2Bfiles%26hl%3Den%26lr%3D%26ie%3DU TF-8%26sa%3DG
http://translate.google.com/translate?hl=en&sl=it&u=http://www.barriodetango.it/midi/Midi.asp&prev=/search%3Fq%3DTango%2Bmidi%2Bfiles%26start%3D20%26hl%3Den%26lr%3D%26ie%3DUTF-8%26 sa%3DN

PS try a 'google' search on "Tango midi files" ......
t.