Yes, and No.

If you have Longhorn Server build 5219, then IIS 7.0 is present. However if you have Vista build 5219* then there is no IIS.

Before anyone asks - Longhorn Server build 5219 is not widely available. No you can't just download it from anywhere.

* Disclaimer I used vista_usa_5219.050830-2010_x86fre_win-dvd.iso - perhaps there are other 5219 Vista builds out there that do have IIS present, but this particular build is the one available from PDC, MSDN Downloads (Sep CTP) and the Connect beta site.