Well that's that. He never specifies he wants any type of error detection, so other than decimal numbers greater than 255, it will not be included. This is the final code for both D2B and B2D. Any suggestions are welcome but this seems to work just fine.

Code:
/*

Craig Wilhelm
18.October.2008
Midterm Assignment
CISP301, TTH, 19:00

18.October.2008
---------------
Initial Scripts

*/

#include <iostream>
#include <string>
using namespace std;

/* CONVERT DECIMAL TO BINARY */

string DtoB(int Decimal);

string DtoB(int Decimal)
{
	int steps[] = {128, 64, 32, 16, 8, 4, 2, 1};
	string binary;

		if(Decimal > 0)
		{
			int stepLen = sizeof(steps) / sizeof(int);
			for(int x = 0; x < stepLen; x++)
			{
			if(Decimal >= steps[x])
				{
				Decimal -= steps[x];
				binary += "1";
				}
			else
				binary += "0";
			}
		}
	else
		binary = "0";

return binary;
}
/* END DECIMAL TO BINARY CONVERSION*/

/* CONVERT BINARY TO DECIMAL */

void BaseGen(int Base[], int Size)
{
Base[0]=1;
int Index=1;
while(Index<Size)
	{
	Base[Index]=Base[Index-1]*2;
	Index=Index+1;
	}
	return ;
}

int BtoD(string Binary)

{ 
	unsigned int Index=1;
  	Index=0;
	int Dv=0;
	int Base[8];
	BaseGen(Base,8);
	while(Index<Binary.size())
	{
		if (Binary[Index]=='1')
			Dv=Dv+Base[Binary.size()-1-Index];
			Index=Index+1;
	}
		return Dv;
}

/* END BINARY TO DECIMAL CONVERSION */

/* BEGIN DP. WHAT SAY YOU? */

int main()
{
	string Bin;	

		cout << "Please type any valid integer no larger than 255: " << endl;
		int Decimal;
		cin >> Decimal;

		if (Decimal > 255)
			{
			cout << "Game Over." << endl;
			system("PAUSE");
			return(0);
			}
		else
			{
			cout << "Binary: " << DtoB(Decimal) << endl;
			}
	
		cout << "Please type any valid binary number of eight or less bits: " << endl;
		int Decimal2;
		cin >> Bin;

		Decimal2=BtoD(Bin);
		cout << "Decimal: " << Decimal2 << endl;
		system("PAUSE");
	
	return(0);
}

/* END DP. WHAT SAY YOU? */