1  LED2+
2  LED1+
3  GND
4  Data0-
5  Data0+
6  Clock-
7  Clock+
8  Data1-
9  Data1+
10 GND
11 
12 
13 
14 
15 SCLK
16 RESET
17 MOSI
18 MISO
19 CS2
20 V18
21 V28
22 CABC
23 LED1-
24 LED2-
ML GND
MR GND

By Peter Bosch
Source: N900 Schematics by NOKIA
11 thru 14 are probably connected to the touch panel ( based on flex connector traces)

1  GND
2  GND
3  GND
4  GND
5  Speaker
6  Speaker
7  GND
8  OUT   (Proximity)
9  INT   (Ambient) 
10 V+    (Ambient,Proximity)
11 GND
12 SDA   (Camera, Ambient)
13 SCL   (Camera, Ambient)
14 GND
15 XSHUTDOWN(Camera) 
16 GND
17 VDIG  (Camera) (Vdigital?)
18 GND
19 VANA  (Camera) (Vanalog?)
20 GND
21 GND
22 CABC  (LCD Connector)
23 GND
24 V18   (LCD Connector)
25 GND
26 V28   (LCD Connector)
27 GND
28 LED1+ (LCD Connector)
29 LED1- (LCD Connector)
30 LED2- (LCD Connector)
31 LED2+ (LCD Connector)
32 GND
33 GND
34 CS2   (LCD Connector)
35 MISO  (LCD Connector)
36 MOSI  (LCD Connector)
37 RESET (LCD Connector)
38 SCLK  (LCD Connector)
39 GND
40 Pin14 (LCD Connector)
41 Pin15 (LCD Connector)
42 GND
43 Pin11 (LCD Connector)
44 Pin12 (LCD Connector)
45 GND
46 D1+   (LCD Connector)
47 D1-   (LCD Connector)
48 CLK+  (LCD Connector)
49 CLK-  (LCD Connector)
50 D0+   (LCD Connector)
51 D0-   (LCD Connector)
52 GND
53 CLKN  (Camera)
54 CLKP  (Camera)
55 GND  
56 DATAN (Camera)
57 DATAP (Camera)
58 GND
59 EXTCLK(Camera)
60 GND
61 B+    (Tricolour LED)
62 R+    (Tricolour LED)
63 G+    (Tricolour LED)
64 GND

By Peter Bosch
Source: N900 Schematics by NOKIA