I found this interesting. You can sign up via your cell phone to follow your favorites on your cell phone( Text messages will be sent on progress of your selected athlete) SIGN UP BEFORE 6AM April 20, Monday.

http://www.baa.org/BostonMarathon/Att-Athlete-Alert.asp

Updates at
Starting line
10k
Half-Marathon
30k
Finish

You have to know bib number, but the elite athletes are listed below

Elite Men
Bib Name Nationality Personal Best
1 Robert K. Cheruiyot KEN 2:07:14
2 Ryan Hall USA 2:06:17
3 Evans Cheruiyot KEN 2:06:25
4 Deriba Merga ETH 2:06:38
5 Daniel Rono KEN 2:06:58
6 Benjamin Maiyo KEN 2:07:09
7 Robert Cheruiyot KEN 2:07:21
8 Gudisa Shentema ETH 2:07:34
9 Gashaw Asfaw ETH 2:08:03
10 Stephen Kiogora KEN 2:08:24
11 Solomon Molla ETH 2:08:46
12 Timothy Cherigat KEN 2:08:34
14 Lee Troop AUS 2:09:49
15 Elijah Sang KEN 2:10:13
16 Brian Sell USA 2:10:47
17 Grigoriy Andreev RUS 2:11:01
18 Iaroslav Musinschi MDA 2:11:43
21 Peter Gilmore USA 2:12:45

Elite Women
Bib Name Nationality Personal Best
F1 Dire Tune ETH 2:24:40
F2 Galina Bogomolova RUS 2:20:47
F3 Bezunesh Bekele ETH 2:23:09
F4 Salina Kosgei KEN 2:23:22
F5 Helena Kiprop KEN 2:25:01
F6 Lidiya Grigoryeva RUS 2:25:10
F7 Atsede Habtamu ETH 2:25:17
F8 Kara Goucher USA 2:25:53
F9 Alice Timbilili KEN 2:26:45
F10 Shuru Deriba ETH 2:28:26
F11 Elva Dryer USA 2:31:48
F12 Adanech Zekiros ETH 2:27:32
F15 Paige Higgins USA 2:33:06