I had implemented the sorting functionality in S-Control. However the same thing can be implemented in Visualforce page. Basically when a User clicks on Header of any column, we will need to call a Controller function.

The controller function will take the name of Column as input. It then needs to sort the list of your data as per the column. Heres how you can do that.

1. Create a List of all records.

2. Create a Map which will store as Key the unique values of the Column you are sorting and Value will be a list of Records which has those values.

3. When Creating a Map, also create a List which will store the unique values of Column you are sorting.

4. Sort the List. ( Apex list has an inbuilt function of Sort. Use that)

5. Using the map, recreate the List of Records in sorted order.

6. Use this records in the page block table.

I am attaching the code of the function that I wrote so that you can understand the steps better

/********************************************

// This function is used for sorting of columns on search result screen

webservice static Saved_Listings__c[] sortLists(Integer x, Saved_Listings__c[] savedLists)

{

try

{

Map<Double,List<Saved_Listings__c>> savedListingsDblMap = new Map<Double,List<Saved_Listings__c>>();

Map<String,List<Saved_Listings__c>> savedListingsStrMap = new Map<String,List<Saved_Listings__c>>();

List<String> strFieldValues = new List<String>();

List<Double> dblFieldValues = new List<Double>();

for(Integer i=0; i<savedLists.size(); i++)

{

List<Saved_Listings__c> temp = new List<Saved_Listings__c>();

// X is used for identifying the column that is to be sorted.

if(x==0)

{

if(savedListingsDblMap.containsKey(savedLists[i].MLS_ID__c))

temp = savedListingsDblMap.get(savedLists[i].MLS_ID__c);

else

dblFieldValues.add(savedLists[i].MLS_ID__c);

temp.add(savedLists[i]);

savedListingsDblMap.put(savedLists[i].MLS_ID__c,temp);

}

if(x==1)

{

if(savedListingsStrMap.containsKey(savedLists[i].Address__c))

temp = savedListingsStrMap.get(savedLists[i].Address__c);

else

strFieldValues.add(savedLists[i].Address__c);

temp.add(savedLists[i]);

savedListingsStrMap.put(savedLists[i].Address__c,temp);

}

if(x==2)

{

if(savedListingsDblMap.containsKey(savedLists[i].Total_Full_Baths__c))

temp = savedListingsDblMap.get(savedLists[i].Total_Full_Baths__c);

else

dblFieldValues.add(savedLists[i].Total_Full_Baths__c);

temp.add(savedLists[i]);

savedListingsDblMap.put(savedLists[i].Total_Full_Baths__c,temp);

}

if(x==3)

{

if(savedListingsDblMap.containsKey(savedLists[i].Total_Bedrooms__c))

temp = savedListingsDblMap.get(savedLists[i].Total_Bedrooms__c);

else

dblFieldValues.add(savedLists[i].Total_Bedrooms__c);

temp.add(savedLists[i]);

savedListingsDblMap.put(savedLists[i].Total_Bedrooms__c,temp);

}

}

List<Saved_Listings__c> sortedSavedLists = new List<Saved_Listings__c>();

if(x==6 || x==0 || x==2 || x==3)

{

dblFieldValues.sort();

for(Integer i=0; i<dblFieldValues.size(); i++)

{

sortedSavedLists.addAll(savedListingsDblMap.get(dblFieldValues[i]));

}

}

else

{

strFieldValues.sort();

for(Integer i=0; i<strFieldValues.size(); i++)

{

sortedSavedLists.addAll(savedListingsStrMap.get(strFieldValues[i]));

}

}

return sortedSavedLists;

}

catch(Exception e)

{

throw e;

}

}

*************************************/

Another addition you can add is to have a boolean variable to decide whether the sorting would be descendin order or Ascending order. I had included that part in the s-control.

Let me know in case of more information.