In our Task Module in MP2 the character limit for the Task number is 20 characters. My question is can I change this to 25 or 30 easily or is there behind the scene problems in doing this? Has anyone done this before.

Typical problem that could arise is reports formats containing this field. Report may show truncated data or data is printed out of line.

Changing the field length in MP2 is not simple, which version are you on? Access, SQL or Oracle?
Have a look at your codes, is there anything you can do with the structure as most MP2 systems I have put in have not had this issue.
If really pushed look at using another non used field that is in the system to hold addtional code information.
This makes filters a little more complex, but makes support and upgrades in the system easy. If you change the field length then every patch and upgrade will be custom and cost $$ ....

SQL

The problem in changing MP2 is the User Interface is in Delphi and the database is SQL, changing the field in SQL is the easy bit, changing the user interface to see the changes is the hard bit.
If you are on SQL, I assume this is version 6.0 ? and not 5.0. In version 6.0 you have the desginer tool in the admin options.
You can use this to add a new table, field or tab and field to the system. This would allow you to add another longer 'code' field to hold your long codes and then use a numeric number in the task number field?