How to create a .BAT file to download and unpack a zip file?

Try this hybrid bat/vbs script

@echo off
 > %temp%\~tmp.vbs echo sUrl = "http://www.unicontsoft.com/file.zip"
>> %temp%\~tmp.vbs echo sFolder = "c:\temp\unzip"
>> %temp%\~tmp.vbs (findstr "'--VBS" "%0" | findstr /v "findstr")
cscript //nologo %temp%\~tmp.vbs
del /q %temp%\~tmp.vbs
goto :eof

'--- figure out temp file & folder
With CreateObject("WScript.Shell")  '--VBS
    sTempFile = .Environment("Process").Item("TEMP") & "\file.zip"  '--VBS 
    sTempFolder = .Environment("Process").Item("TEMP") & "\file.zip.extracted"  '--VBS
End With    '--VBS

'--- download
WiTh CreateObject("MSXML2.XMLHTTP") '--VBS
    .Open "GET", sUrl, false    '--VBS
    .Send() '--VBS
    If .Status = 200 Then   '--VBS
        ResponseBody = .ResponseBody    '--VBS
        With Createobject("Scripting.FileSystemObject") '--VBS
            If .FileExists(sTempFile) Then  '--VBS
                .DeleteFile sTempFile   '--VBS
            End If  '--VBS
        End With    '--VBS
        With CreateObject("ADODB.Stream")   '--VBS
            .Open   '--VBS
            .Type = 1 ' adTypeBinary    '--VBS
            .Write ResponseBody '--VBS
            .Position = 0   '--VBS
            .SaveToFile sTempFile   '--VBS
        End With    '--VBS
    End If  '--VBS
End With    '--VBS

'--- extract
With CreateObject("Scripting.FileSystemObject") '--VBS
    On Error Resume Next    '--VBS
    .CreateFolder sFolder   '--VBS
    .DeleteFolder sTempFolder, True '--VBS
    .CreateFolder sTempFolder   '--VBS
    On Error GoTo 0 '--VBS
    With CreateObject("Shell.Application")  '--VBS
        .NameSpace(sTempFolder).CopyHere .NameSpace(sTempFile).Items    '--VBS
    End With    '--VBS
    .CopyFolder sTempFolder, sFolder, True  '--VBS
    .DeleteFolder sTempFile, True   '--VBS
    .DeleteFile sTempFile, True '--VBS
End With    '--VBS

If you really want to use a bat-file you may have a look at: http://www.chami.com/tips/windows/062598W.html

The batch file will use a command-line-tools called: URL2File

EDIT: Your batch file should look something like (you need to have pkunzip or another cmd-line tool (7-zip f.e.) installed for that)

@echo off
c:
cd\files
URL2File http://www.server.com/file1.zip file1.zip

for %%f in (file1.zip) do pkunzip %%f c:\user\unziped_files\%%f\

You can use curl to download the files.

The manual includes several examples