Adding a node to a linked list

I'm having the worst time trying to add a node into a linked list. I can't even get the node in. My instructor said this would work, but I think he must have read it over too quickly. The list is supposed to be in ascending order of Zip codes.

Code:

struct SListNode{
   char City[41];
   char State[3];
   char Zip[6];
   double Longitude;
   double Latitude;
   long Population;
   struct SListNode *Next;
   struct SListNode *Prev;
   };

void vAddListNode (struct SListHeader *psList, struct SListNode *psNode)
   {
   struct SListNode *psNext=NULL;
   int comp;
   psList->iNodeCount = psList->iNodeCount+1;
   psNext = psList->psHead;
   comp = strcmp(psNode->Zip, psNext->Zip);
   while (comp > 0)
      {
      psNode->Next = psNext;
      psNode->Prev = psNext->Prev;
      psNode->Next->Prev = psNext;
      psNode->Prev->Next = psNext;
      psNext = psNode->Next;
      printf("City5:  %s", psNext->City);
      printf("City5:  %s", psNode->City);
      comp = strcmp(psNode->Zip, psNext->Zip);
      }
   }

I'am just posting here, don't forget to add the code tags, you need to open it and close it [] and [/].

Without this, your code look bad

I've figured this out so don't worry about it.

Scott