Ethereal also comes with tethereal which will run fine from just a tty. You can also use tethereal (or another packet sniffer such as tcpdump or snoop) to dump traffic to a file and then pull the results back to your local machine to dissect them using the full power of the Ethereal GUI.

Update: Just to clarify, tethereal has no X parts and will spit out most of the same information as ethereal can:

  0.021897 199.242.139.15 -> 199.242.139.11 HTTP HEAD / HTTP/1.1

0000  00 10 4b 66 c1 93 00 e0 29 27 1a ae 08 00 45 00   ..Kf....)'....
+E.
0010  00 a8 c2 54 40 00 3f 06 d2 fb c7 f2 8b 0f c7 f2   ...T@.?.......
+..
0020  8b 0b d8 89 00 50 67 3b 94 99 0d bf 1c 41 80 18   .....Pg;.....A
+..
0030  82 18 89 7b 00 00 01 01 08 0a 07 2d 1c 04 07 2d   ...{.......-..
+.-
0040  1c 02 48 45 41 44 20 2f 20 48 54 54 50 2f 31 2e   ..HEAD / HTTP/
+1.
0050  31 0d 0a 54 45 3a 20 64 65 66 6c 61 74 65 2c 67   1..TE: deflate
+,g
0060  7a 69 70 3b 71 3d 30 2e 33 0d 0a 43 6f 6e 6e 65   zip;q=0.3..Con
+ne
0070  63 74 69 6f 6e 3a 20 54 45 2c 20 63 6c 6f 73 65   ction: TE, clo
+se
0080  0d 0a 48 6f 73 74 3a 20 70 68 79 64 65 61 75 78   ..Host: phydea
+ux
0090  2e 6f 72 67 0d 0a 55 73 65 72 2d 41 67 65 6e 74   .org..User-Age
+nt
00a0  3a 20 6c 77 70 2d 72 65 71 75 65 73 74 2f 32 2e   : lwp-request/
+2.
00b0  30 31 0d 0a 0d 0a                                 01....

  0.027344 199.242.139.11 -> 199.242.139.15 HTTP HTTP/1.1 200 OK

0000  00 e0 29 27 1a ae 00 10 4b 66 c1 93 08 00 45 00   ..)'....Kf....
+E.
0010  00 ec c2 55 40 00 40 06 00 00 c7 f2 8b 0b c7 f2   ...U@.@.......
+..
0020  8b 0f 00 50 d8 89 0d bf 1c 41 67 3b 95 0d 80 18   ...P.....Ag;..
+..
0030  82 18 a6 de 00 00 01 01 08 0a 07 2d 1c 05 07 2d   ...........-..
+.-
0040  1c 04 48 54 54 50 2f 31 2e 31 20 32 30 30 20 4f   ..HTTP/1.1 200
+ O
0050  4b 0d 0a 44 61 74 65 3a 20 4d 6f 6e 2c 20 32 30   K..Date: Mon, 
+20
0060  20 53 65 70 20 32 30 30 34 20 31 36 3a 32 31 3a    Sep 2004 16:2
+1:
0070  34 35 20 47 4d 54 0d 0a 53 65 72 76 65 72 3a 20   45 GMT..Server
+:
0080  41 70 61 63 68 65 2f 31 2e 33 2e 33 31 20 28 55   Apache/1.3.31 
+(U
0090  6e 69 78 29 20 44 41 56 2f 31 2e 30 2e 33 20 6d   nix) DAV/1.0.3
+ m
00a0  6f 64 5f 70 65 72 6c 2f 31 2e 32 39 20 6d 6f 64   od_perl/1.29 m
+od
00b0  5f 73 73 6c 2f 32 2e 38 2e 31 39 20 4f 70 65 6e   _ssl/2.8.19 Op
+en
00c0  53 53 4c 2f 30 2e 39 2e 36 65 0d 0a 43 6f 6e 6e   SSL/0.9.6e..Co
+nn
00d0  65 63 74 69 6f 6e 3a 20 63 6c 6f 73 65 0d 0a 43   ection: close.
+.C
00e0  6f 6e 74 65 6e 74 2d 54 79 70 65 3a 20 74 65 78   ontent-Type: t
+ex
00f0  74 2f 68 74 6d 6c 0d 0a 0d 0a                     t/html....
[download]

But you can't do things like use the "follow this connection" tool which the Ethereal GUI provides.