Yes, the protocol is standardized by RFC2246 so any implementation that claims to support the RFC should work, including not just Sun and IBM JSSE but also C/C++ clients via OpenSSL &c.
There is a small gotcha in that the IBM JSSE supports SSL 2.0 and I think more cipher suites than Sun's (who don't support 2.0 either), but they should be able to negotiate a communication if left to themselves.