You can use the SSI.php to include most of the features in your site. There is a thread on this board about this.
http://www.yabb.info/community/index.php?board=154;action=display;threadid=4194Also you can find the login HTML code from your board and just paste it on your site and it works.
I have this code on my sites front page:
<FORM ACTION="http://www.kotichat.com/forum/index.php?board=;action=login2" METHOD="POST" TARGET="_blank">
<TABLE CLASS="text1" WIDTH="100%" CELLSPACING="0" CELLPADDING="3" ALIGN="RIGHT">
<TR VALIGN="TOP">
<TD COLSPAN="2">
<H5><IMG SRC="http://www.kotichat.com/forum/YaBBImages/login_sm.gif" ALT="">
<B>Login to discussion area</B> </H5>
</TD>
</TR>
<TR>
<TD ALIGN="right"><B>Username:</B></TD>
<TD><FONT SIZE=2>
<INPUT TYPE=text NAME="user" SIZE=15>
</FONT></TD>
</TR>
<TR>
<TD ALIGN="right"><B>Password:</B></TD>
<TD>
<INPUT TYPE=password NAME="passwrd" SIZE=15>
</TD>
</TR>
<TR>
<TD ALIGN="right"><B>Session length:</B></TD>
<TD>
<INPUT TYPE=text NAME="cookielength" SIZE=4 MAXLENGTH="4" VALUE="60">
</TD>
</TR>
<TR>
<TD ALIGN="right"><B>Stay always logged inside:</B></TD>
<TD>
<INPUT TYPE=checkbox NAME="cookieneverexp">
</TD>
</TR>
<TR>
<TD ALIGN=center><BR>
<INPUT TYPE=submit VALUE="Login" NAME="submit">
</TD>
</TR>
<TR>
<TD ALIGN=center><A HREF="http://www.kotichat.com/forum/Reminder.php?action=input_user">Forgot
your password?</A><BR>
<BR>
</TD>
</TR>
</TABLE>
</FORM>