Yes, Yahoo! Inc. has registered both of those domains, in addition to their real one. Here is the registrant info:

Registrant:
Yahoo! Inc.
(DOM-269234)
701 First Avenue Sunnyvale
CA
94089 US

Domain Name: yhaoo.com

Registrar Name: Alldomains.com
Registrar Whois: whois.alldomains.com
Registrar Homepage: http://www.alldomains.com

Administrative Contact:
Domain Administrator
(NIC-1373476)
Yahoo! Inc.
701 First Avenue Sunnyvale
CA
94089 US
[email protected] +1.4083493300 Fax- +1.4083493301
Technical Contact, Zone Contact:
Domain Administrator
(NIC-1372925)
Yahoo! Inc.
701 First Avenue Sunnyvale
CA
94089 US
[email protected] +1.4083493300 Fax- +1.4083493301

Created on..............: 1999-Nov-23.
Expires on..............: 2005-Nov-23.
Record last updated on..: 2003-Apr-07 10:42:46.

Domain servers in listed order:

NS1.YAHOO.COM 66.218.71.63
NS5.YAHOO.COM 216.109.116.17
NS2.YAHOO.COM 66.163.169.170
NS3.YAHOO.COM 217.12.4.104
NS4.YAHOO.COM 63.250.206.138