NSS implements SSL v2 and v3, TLS, PKCS#5, PKCS#7, PKCS#11, PKCS#12, S/MIME, X.509v3 certificates, and other security standards. These libraries are used by Mozilla / Netscape Communicator and server products. [Open Source]
It includes everything needed for delivering SSL-enabled applications developed in C, C++, or Java. It is not subject to US export control. [Commercial] (RSA Data Security)
MatrixSSL is an open source embedded SSL implementation under 50K. It is designed for small footprint devices and applications requiring low connection overhead.