In SharePoint Designer from the email  Action you will be presented
with the define email message box. From the Address book icon you
can choose "Workflow lookup" from the Select Users list.

Are the fields in your InfoPath form  set as "promoted properties"?
For details, see the "Add, remove, or modify document library  columns
or site columns" topic in InfoPath Help. Promoting the properties
will make them visible as columns in the SharePoint form library.

You can send an email  to a specific group based  on the value in the
form using conditional branches -- e.g.,

Condition: if category = Blue
Action: Send Email to Blue Approvers

Condition: if category = Red
Action: Send Email to Red Approvers

Another method would be:

Step 1 - create an Action: Build Dynamic String that stores the
category (or other form value) in a variable. For example, store
[lookup:category] Approvers in varSendMailTo.

Step 2 - create an Action: Send Email
Set the To field equal to a Workflow Variable > varSendMailTo

On your SharePoint site, create groups  as Red Approvers, Blue
Approvers, etc.

I think I found the solution to my problem. Basically, within my
workflow I can look at workflowProperties.Item.File.OpenBinaryStream()
to get the xml. I them deserialize this to the form  object that I
created using the xsd utility. At that point I can access  any of the
fields I need without needing to promote additional columns. Thanks for
everyone's help.

I am creating an Incident Report workflow. I seem to have everything set up
correctly with the exception of users being able viewing the review
committee and final approver's comments. The review committee does not want
the submitter to have access  to their comments. I am sure there is a simple
solution t this, but need a hand.

My only suggestion is to put the reviewer comments into a different but related
list. Connected Web Parts could show the comments for each list item to those
that have access  but those that don't wouldn't see any comments.

I think I can do something with the connected web parts. As for your
other comment... I created the basic  incident report and from there I
created a first level workflow  and then created a final approval workflow. I
have my test users set up with contributor permission, and my two test
reviewers set up with Full Control. Everything is working okay except for
when it comes to approvals. At this point as I stated before, the submitter
can see that their report was approved, but can see the reviewers' comments.
I also set up the workflow permissions are only available to the reviewers.

I apologize if I am not getting it. End of week, vacation starts in 2 hrs,
so maybe my brain is wrapping around your suggested solution.

WSS v3 doesn't have column level security and v4 probably won't either. So, the
best thing that you can do is to create a one to one relationship with the
"basic incident report" list and store the comments in that related list rather
than the main list.

That makes a little more sense to me for some reason. I'll give it a go.

Another possible solution is to modify the form  using Conditional Formatting in
SharePoint Designer.