How to select a value with a column name that also needs selected?

The SQL Server 2005 table I'm working from is really strange. Here's an example:

   key | a | b | c | d | e | f 
z   0   1   2   3   4   5   6
y   1   8   9  10  11  12  13
x  14  15  16  17  18  19  20 
w  21  22  23  24  25  26  27

What I need to accomplish is to, in a single statement, select the column name from a different table, then get the value here. So it would be something like "Select (select colName from table2 where id=VAR1) From table1 where key = VAR2" So table2 will return either a/b/c/d/e/f, and then the main statement will get the value of the corresponding value based on the key. Table2 will always return a-f, and I will know the VAR1 and VAR2 ahead of time.