Online tutorial service TheTutorialChannel.com (TTC) yesterday signed a letter of intent to acquire Knowledge Base Inc., an educational consulting firm, in an effort to boost its ability to make Internet learning programs. Terms were not disclosed. TTC, the interactive unit of direct marketer Multimedia Tutorial Services Inc., Brooklyn, NY, also expects the acquisition to strengthen its hand in obtaining sponsorships from corporations and educational organizations. Knowledge Base has marketed learning products and motivational programs to numerous primary schools and colleges. The firm also has performed management consulting for companies including Nike, AT&T and publisher Prentice Hall. Multimedia Tutorial also sells telemarketing services to other Net firms.