At this point in their lives, you'd think multi-instrumentalist songbirds Kate and Anna McGarrigle would be able to line up a simple distribution deal without too much trouble: They've been hit songwriters (the Linda Ronstadt title track "Heart Like a Wheel" is Anna's), musicians' musicians, and objects of cult veneration since the mid-70s. Kate's son, Rufus Wainwright, has grown up to be a big pop star. Their eighth album, The McGarrigle Hour (Hannibal, 1998), an extended-family-assisted salmagundi of folk tunes, Victorian parlor songs, and highlights from their own songbook, was a critical favorite, a solid seller, and a thing of great beauty. So how come their ninth and latest, La vache qui pleure (La Tribu, 2003), remains unavailable in America months after its European release? Reportedly it comprises ten folk numbers in French (plus an English version of one) and bears a strong musical resemblance to their gorgeous 1980 francophone release, The French Record. (The McGarrigles were raised in Quebec's Laurentian Mountains and grew up speaking French at school and English at home.) Now in their late 50s, the sisters are still in superb voice, and their harmonies retain that genetic stamp shared by great sibling vocal teams like the Everlys and the Louvins. Their repertoire is superb as well: Anna's serene "Cool River" probably ought to be banned for being too tempting to the suicidally inclined. The early show is sold-out. Friday, February 13, 7:30 and 10 PM, Old Town School of Folk Music, 4544 N. Lincoln; 773-728-6000.