What is the difference between Intel TXT and TPM?

What is the difference between Intel TXT and TPM? What more Intel TXT has to offer as compared to TPM? Basically, I wanted to know how TXT works? Any easy to follow literature for beginners will be highly appreciated!

Scolytus is right but let me explain a bit more.

As he said, a TPM is a dependency of TXT but not the other way around. The TPM is where TXT will store the measurements - hash of components - of the platform. If TXT is not supported by a platform but a TPM is still present you still have all these features:

• Integrity measurement – securely measure the platform's components (hashes stored within the TPM)
• Authenticated boot – a process by which a platform's state (the sum of its components) is reliably measured and stored. SRTM - Static Root of Trust for Measurements
• Sealed Storage - encrypt data based on the current state of the platform or in other words, what has been measured (the PCR hash values stored in the TPM) - seal operation
• Attestation - securely report to other parties the state of the platform, e.g., quote operation aka Remote Attestation.

As such you could use trustedgrub (SRTM - Static Root of Trust for Measurements) but not tboot which implements a DRTM (Dynamic Root of Trust for Measurements) aka TXT.

About "how TXT works" see this question.