Regex help needed

Hello, Well I am doing by first reg ex operations and I am having problems which I just cannot figure out. For example I tried echo eregi_replace ("<tr bgcolor=\"#F8F8F1\">(\s*)<td>\s*<font size=\"2\">\s*purchasing power parity", '%POWER%', '<td><tr>sdsdss<tr bgcolor="#f8f8f1"><td><font size="2">Purchasing power parity'); and this worked perfectly, but when I chnaged that to echo eregi_replace ("<tr bgcolor=\"#F8F8F1\">(\s*)<td>\s*<font size=\"2\">\s*purchasing\s+power\s+parity", '%POWER%', '<td><tr>sdsdss<tr bgcolor="#f8f8f1"><td><font size="2">Purchasing power parity'); It does not detect the string. Srange. According to what I know, \s+ will detect a single space also. I tried chnaging the last 2 \s+ to \s* but this did not work also. Any ideas on this one? As I proceed I would like the expression to detect the optional face attribute also, so I tried echo eregi_replace ("<tr bgcolor=\"#F8F8F1\">(\s*)<td>\s*<font size=\"2\"(\s+face=\"Verdana, Arial, Helvetica, sans-serif\"|)>\s*purchasing power parity", '%POWER%', '<td><tr>sdsdss<tr bgcolor="#f8f8f1" face="Verdana, Arial, Helvetica, sans-serif"><td><font size="2">Purchasing power parity'); ... and this gave me an error like Warning: eregi_replace(): REG_EMPTY:çempty (sub)expression in D:\sid\dg\test.php on line 2 Any ideas? BTW any place where I can get started on regex? I got a perl book that explains regex, but I have got to learn perl first (I dont know any perl) Thanks in advance. - Sid