Can you post your code here? I can try to identify the possible error..

And yes, the document does'nt cover this topic, But when you view the actual generated HTML you can atleast come to a conclusion if it can be done or not..

The actual code I'm working on is a pretty daunting sight, so just as an example I've cobbled together some code based on this example elsewhere on the boards that should roughly illustrate the idea. That previous thread covers the intended functionality of most of the code, and I've just added in the formatting stuff. It ain't the prettiest thing ever, but still.

Here's the Apex:

public class PersonExtension{
public string sRowClasses;

public string getRowClasses(){
return sRowClasses;
}

private final Contact person;

public PersonExtension(ApexPages.StandardController stdController){
this.person= (Contact)stdController.getRecord();
}
public class People {
contact c;
public People(Contact cin) { c = cin; }
public Contact getContact(){ return c;}
public String getAgeType() {
if (c.Age__c == null ){
sRowClasses = sRowClasses + 'cUnknown,'
return 'unknown';
}else if (c.age__c < 21){
sRowClasses = sRowClasses + 'cMinor,'
return 'minor';

}else{
sRowClasses = sRowClasses + 'cAdult,'
return 'adult';
}
}
}
List<People> peeps = new List<People>{};
public List<People> getPersonList() {
peeps.clear();
for (contact cc: [Select p.Id, p.Name, p.Age__c from Contact p order by lastname limit 10] ) {
peeps.add( new People (cc) );
}
return peeps;
}

public String getAnyString(){
return 'Anything';
}
}

 And here's the VisualForce:

<apex:page standardController="Contact" extensions="PersonExtension">
<style>
.cUnknown{
background:#cccccc;
}
.cMinor{
background:#ff9999;
}
.cAdult{
background:#99ff99;
}
</style>
<apex:form>
<apex:pageblock title="My Persons Infos">
<apex:pageblockList value="{!PersonList}" var="p" rowclasses="{!RowClasses}">
<apex:column value="{!p.Contact.Name}"/>
<apex:column value="{!p.Contact.Age__c}"/>
<apex:column value="{!p.ageType}" headerValue="Adultness" />
<apex:column value="{!anystring}" headerValue="my String" />
</apex:pageblockList>
</apex:pageblock>
</apex:form>
</apex:page>