[рони]

L0k1,

var arr = [
 ['a1','a2','a3'],
 ['b1','b2'],
 ['c1','c2']
]
;
function go(b) {
    for (var a = 0; a < b.length - 1; a++) {
        for (var c = [], d = 0 ; d < b[a].length; d++)
            for (var e = 0; e < b[a + 1].length; e++) c.push(b[a][d] + " " + b[a + 1][e]);
        b[a + 1] = c
    }
    return c
};
alert(go(arr).join('\n'))