Obviously no download yet, but I found the official tracklist for the OST!
I found it on the Japanese Square Enix website but it also has the English tracklist as well as the Japanese one.

EDIT:
I just pre-ordered the soundtrack and whenever I get it, I'll rip the CDs and upload it for a free download.

Anyway, here it is!

01.Somnus (Instrumental Version)
02.Departure
03.Broken Down
04.Hammerhead
05.Wanderlust
06.Encroaching Fear
07.Stand Your Ground
08.Relax and Reflect
09.Day's End Fanfare
10.Horizon
11.Safe Haven
12.Lurking Danger
13.Hunt or Be Hunted
14.CINDY
15.End of the Road
16.A Quick Pit Stop
17.Love Lost
18.Galdin Quay
19.ARDYN
20.The Aggressors
21.NOX AETERNA
22.The Hunters
23.What Lies Within
24.Daemons
25.Bros on the Road
26.Fantastica!
27.The Niflheim Empire
28.Veiled in Black
29.Valse di Fantastica
30.Crystalline Chill
31.What a Hoot
32.Blues de Chocobo
33.Reel Rumble
34.The Fight Is On!
35.Lestallum
36.Welcome to the Leville
37.Unsettling Aura
38.Don't Panic!
39.APOCALYPSIS NOCTIS
40.Cosmogony
41.Melancholia
42.A Premonition
43.NOX DIVINA
44.Labyrinthine
45.Flying R
46.Imperial Infiltration
47.Veiled in Black (Arrangement)
48.Invidia
49.Sorrow Without Solace
50.Sunset Waltz
51.Disquiet
52.OMNIS LACRIMA
53.Rodeo de Chocobo
54.Listen Up
55.Creeping Shadows
56.Impending Peril
57.Up for the Challenge
58.Cape Caem
59.Cape Caem - Our New Home
60.Cape Caem - Hidden Harbor
61.Bros on the Road II
62.NOCTIS
63.Over the Waves
64.Altissia
65.Altissia - Gondola Ride
66.Welcome to the Royal Suite
67.Starlit Waltz
68.Prayer de LUNA
69.No Time Left
70.Song of the Stars
71.The Hydraean's Wrath
72.ARDYN II
73.LUNA
74.APOCALYPSIS AQUARIUS
75.Broken Bonds
76.Dining Car
77.Cartanica
78.Relax and Reflect - Pensive
79.Careening Into Danger
80.Tenebrae
81.Horrors of the Night
82.End of the Road
83.An Empire in Ruins
84.RAVUS AETERNA
85.In the Light of the Crystal
86.A World Unwaking
87.Neverending Nightmare
88.Homecoming
89.Hammerhead - The Last Bastion
90.Somnus
91.Hellfire
92.Magna Insomnia
93.Dawn
94.Somnus Ultima
95.Dewdrops at Dawn
96.Main Theme from FINAL FANTASY

Here's the link to the list if you want to have a look for yourselves:
http://www.square-enix.co.jp/music/sem/page/ff15/ost/en/tracklist/

Cool. Thanks :)