Well today I was pleasantly surprised when I did an SVN update and saw several changes to wmap, when reading the documentation I was even more surprised by seeing that basic reporting was added!!! know this is something that I have always found laking in MSF and seeing it in wmap really makes me happy, I do hope that the project keeps improving like it has been so far.
Information from the documentation:

Each module is capable of storing reporting information.
Reporting key concepts:

+ Reporting is used to gather and store data
+ Bye bye to useless risk levels
+ Data is not only findings (i.e vulnerabilities) but also any relevant
data (i.e. Database name from a SQL injection)
+ Data is available to other modules so reporting becomes a method to
share information
+ Data has context and that context is preserved.
+ Context is preserved by having a tree structure in the Report database
table
+ Every report entry has a parent_id the top parent_id is 0 and only used
to create a report entry (this allows for the storage of multiple reports)
+ The report table is basically a type,name,value database.
+ This schema allows the storage of data/vulnerabilities with any classification/naming
convention. (very useful to store vulnerabilities discovered in year 2060).

So how it works:

When q module is executed (using WMAP 'wmap_run -e' or standalone):

WMAP creates a new report entry, then in each module when something is found or
something needs to be reported the module should implement the following lines:

Example:

if (vulnerability is found)
print_status("FOUND BLAH BLAH BLAH")

#OBTAIN THE LATEST REPORT ID FOR HOST,PORT,SSL (target)
rep_id = wmap_base_report_id(
self.target_host,
self.target_port,
self.ssl
)

# REPORT ABOUT THE FINDING
vuln_id = wmap_report(rep_id,'VULNERABILITY','SQL_INJECTION',url_path,"A SQL injection
vulnerability was found in the following URL in the parameter 'test'")

# LETS SAY WE NEED TO STORE ALSO THE PARAMETER VULNERABLE TO THE INJECTION AND THE TYPE
# OF INJECTION.

NOTE: wmap_report() returns the id of this entry

wmap_report(vuln_id,'SQL_INJECTION','PARAMETER',parameter,"Notes balh blah")
wmap_report(vuln_id,'SQL_INJECTION','TYPE','String',"Notes 2 balh blah")
end

If you are connected to a database (db_connect) then reporting is active and every module executed will
store its results for reporting. Even if you define a RHOSTS range then the results auto-magically will
be organized per host,port as wmap_base_report_id() returns the last available report for the specified
host,port,ssl target.

Anything can be represented and reported and other modules will have access to this information to do
whatever they want.

To view available reports use the 'wmap_reports' command:

msf > load db_sqlite3
[*] Successfully loaded plugin: db_sqlite3
msf > load db_wmap
[*] =[ WMAP v0.2 - ET LoWNOISE
[*] Successfully loaded plugin: db_wmap
msf > db_connect
[*] Successfully connected to the database
[*] File: /Users/et/.msf3/sqlite3.db
...
msf > wmap_reports -p
[*] Id. Created Target (host,port,ssl)
1. Wed Oct 22 23:22:16 -0500 2008 XX.XXX.XXX.XXX,80,0
[*] Done.
msf > wmap_reports -s 1
WMAP REPORT: XX.XXX.XXX.XXX,80,0 Metasploit WMAP Report [Wed Oct 22 23:22:16 -0500 2008]
WEB_SERVER TYPE: Apache [Wed Oct 22 23:22:16 -0500 2008]
VULNERABILITY SQL_INJECTION: /test.asp SQL injection found. [Wed Oct 22 23:22:31 -0500 2008]
SQL_INJECTION PARAMETER: id [Wed Oct 22 23:22:31 -0500 2008]
SQL_INJECTION TYPE: String [Wed Oct 22 23:22:31 -0500 2008]
[*] Done.