Well, it took me a while to work out Linking to a report (and setting parameters). Now it works, but I must click Run after I reach the page. I want to skip that step. can you help?

So here's my Link URL:

https://emea.salesforce.com/00O20000002IIGT?colDt_q=custom&colDt_s=07/02/2009&colDt_e=07/02/2009

 It takes me to ther report, now I just have to click Run, and the report works.

Explenation and things I've learned on the way:

1. in order to set a date, one needs to set three parameters in the url: 
   colDt_q, colDt_s, colDt_e (example, just so you can see the date format: colDt_q=custom&colDt_s=23/05/2009&colDt_e=10/03/2010)
2. Salesforce uses many date formats, sometime a date is produced in YYYY-MM-DD format, but here, I need the DD/MM/YYYY (notice, DD, and MM must be 2 digits long)In order to produce a link with the properly formatted date, I had to create the following cumbersome formula field:

IF(LEN(TEXT(DAY( Week_Ending__c )))=1,"0"&TEXT(DAY( Week_Ending__c )),TEXT(DAY( Week_Ending__c )))&'/'&IF(LEN(TEXT(MONTH( Week_Ending__c )))=1,"0"&TEXT(MONTH( Week_Ending__c )),TEXT(MONTH( Week_Ending__c )))&'/'&TEXT(YEAR(Week_Ending__c ))

 (The point here is adding the leading '0' in case the week or month is one digit long)

3. Just a note: a proper URL format replaces '/' in the date parameter with a %2F 

4. Read this: http://sfdc.arrowpointe.com/2005/06/09/auto-create-reports-from-web-links/

5. Read this: http://community.salesforce.com/sforce/board/message?board.id=general_development&message.id=22031