The following entries will configure Apache (1.3.2) to dump request/reply header information:

#
# Minimal request/reply header logging
#
LogFormat "\n\
\n\
%t %h\n\
%r\n\
Cache-Control: %{Cache-Control}i\n\
Authorization: %{Authorization}i\n\
\n\
%s\n\
Cache-Control: %{Cache-Control}o\n\
Server: %{Server}o\n\
WWW-Authenticate: %{WWW-Authenticate}o\n\
%b" headers
#CustomLog logs/headers.log headers

#
# Full request/reply header logging
#
LogFormat "\n\
\n\
%t %h\n\
%r\n\
Cache-Control: %{Cache-Control}i\n\
Connection: %{Connection}i\n\
Date: %{Date}i\n\
Pragma: %{Pragma}i\n\
Trailer: %{Trailer}i\n\
Transfer-Encoding: %{Transfer-Encoding}i\n\
Upgrade: %{Upgrade}i\n\
Via: %{Via}i\n\
Warning: %{Warning}i\n\
Accept: %{Accept}i\n\
Accept-Charset: %{Accept-Charset}i\n\
Accept-Encoding: %{Accept-Encoding}i\n\
Accept-Language: %{Accept-Language}i\n\
Authorization: %{Authorization}i\n\
Expect: %{Expect}i\n\
From: %{From}i\n\
Host: %{Host}i\n\
If-Match: %{If-Match}i\n\
If-Modified-Since: %{If-Modified-Since}i\n\
If-None-Match: %{If-None-Match}i\n\
If-Range: %{If-Range}i\n\
If-Unmodified-Since: %{If-Unmodified-Since}i\n\
Max-Forwards: %{Max-Forwards}i\n\
Proxy-Authorization: %{Proxy-Authorization}i\n\
Range: %{Range}i\n\
Referer: %{Referer}i\n\
TE: %{TE}i\n\
User-Agent: %{User-Agent}i\n\
\n\
%s\n\
Cache-Control: %{Cache-Control}o\n\
Connection: %{Connection}o\n\
Date: %{Date}o\n\
Pragma: %{Pragma}o\n\
Trailer: %{Trailer}o\n\
Transfer-Encoding: %{Transfer-Encoding}o\n\
Upgrade: %{Upgrade}o\n\
Via: %{Via}o\n\
Warning: %{Warning}o\n\
Accept-Ranges: %{Accept-Ranges}o\n\
Age: %{Age}o\n\
ETag: %{ETag}o\n\
Location: %{Location}o\n\
Proxy-Authentication: %{Proxy-Authentication}o\n\
Retry-After: %{Retry-After}o\n\
Server: %{Server}o\n\
Vary: %{Vary}o\n\
WWW-Authenticate: %{WWW-Authenticate}o\n\
%b" full-headers
#CustomLog logs/full-headers.log full-headers