Just a side note: the 'c' in ctime doesn't stand for "create" (a common misconception, though). Better think of it as "change", as it refers to when the file's status (i.e. inode meta information) was last changed.

Now, you may wonder what the difference then is to modification time (mtime)...  The latter isn't updated when you change the mode/owner/group of the file, or the link count changes, etc.  For example:

#!/bin/sh

rm -f foo
touch foo
stat foo
sleep 3
echo bar >>foo
stat foo
sleep 3
chmod o-r foo     # changes ctime only
stat foo
[download]

Output:

  File: `foo'
  Size: 0             Blocks: 0          IO Block: 4096   regular empt
+y file
Device: 811h/2065d    Inode: 36356982    Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/   almut)   Gid: ( 1000/   almu
+t)
Access: 2010-05-15 11:08:00.000000000 +0200
Modify: 2010-05-15 11:08:00.000000000 +0200
Change: 2010-05-15 11:08:00.000000000 +0200
  File: `foo'
  Size: 4             Blocks: 8          IO Block: 4096   regular file
Device: 811h/2065d    Inode: 36356982    Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/   almut)   Gid: ( 1000/   almu
+t)
Access: 2010-05-15 11:08:00.000000000 +0200
Modify: 2010-05-15 11:08:03.000000000 +0200     <---
Change: 2010-05-15 11:08:03.000000000 +0200     <---
  File: `foo'
  Size: 4             Blocks: 8          IO Block: 4096   regular file
Device: 811h/2065d    Inode: 36356982    Links: 1
Access: (0640/-rw-r-----)  Uid: ( 1000/   almut)   Gid: ( 1000/   almu
+t)
Access: 2010-05-15 11:08:00.000000000 +0200
Modify: 2010-05-15 11:08:03.000000000 +0200
Change: 2010-05-15 11:08:06.000000000 +0200     <---
[download]

As you can see, the file was modified before it had been created... ;)