Perl and asp are completely different routes to the same end. That is, yes, they can both achieve the same results. Differeneces are:
1. ASP mostly runs on the client. That is, when you view an asp page, your computer downloads the script and executes it. Perl is run at the server. So, the server's processor and memory are used to run the code. ASP can be set to run at the server (in some cases it has to), but that's usually the exeption, not the rule.
2. Perl is much, much faster. This is because first of all, there's no download time (it runs right on the server) but secondly because perl is a language of its own, and runs in an open, pretty unrestricted manner. Perl scripts can also get a lot of help from a well-configured server. The VB or VB script incorporated in ASP requires a scripting environment to be set up on the client computer, and is actually a bit cumbersume and demands a decent chunk of memory.
3. Since perl is right on the server, it makes it a lot easier to send an email attached to a form. There are no authorization problems like there may be with asp.
4. ASP is (usually) easier to work with, maybe only because there's plenty of software available to work with it. But, given a choice, I would go with perl. I use asp for web-based database functions, only because I'm more familiar with it in that sense.