VPN implementation

[Dennis Nwaigbo <dnwaig () ctp com>]

Hello gangs,
 I am building a VPN solution for our company.  What I am trying to do is
build a VPN through the internet so that my users can have a secure data
access at the corporate headquarters through the corporate WAN.  The
environment is purely NT shop. The intent is to use native PPTP for
connectivity.  

My questions are as follows:
*       I intend to use the native PPTP for connectivity.  What are the ups
and downs of this protocol for this solution?
*       What are the security ramifications for using PPTP instead of IPSec?
*       What should I worry about as I embark on this project in terms of
Security, performance, uptime?  
*       I also intend to go through an ISP.  What should I worry about on
the ISP side?
*       What hard-hitting questions should I pose to the ISP especially for
SLA?

I will appreciate any comments, references, pointers, suggestions, warnings,
etc.

cheers,
Dennis Nwaigbo (w-e-e-bo)   
Sr. Network Architect
>  /\/\  Cambridge Technology Partners, Inc.
> / /_ \ 2828 Routh Street, Suite 825
> \  / /        Dallas, Texas  75201.  Phone: 214-860-1274 . 
>  \/\/  Fax:  214-860-1400,  mailto:dnwaig () ctp com