Over in the Loosely Coupled blog, Phil Wainewright shares his insight about "brownfield development." He's right on target (as usual) about the fact that Web Services projects generally involve leaving existing structures and applications in place while building around them.
Phil mentions a couple of vendors in his posting, but IMO there's no better system for "brownfield" web services development than Artix. Artix is purpose-built for brownfield development. Its innovative application of WSDL for middleware integration is unmatched in the industry.
You want to leave an existing service in place and, without touching it, make it accessible to a wide variety of callers, even if those callers are implemented on different middleware than the service? Put Artix in front of it. Artix will speak to the service using its native protocol, transport, and on-the-wire format, such that Artix appears to the service as a normal native caller. To other callers, however, Artix appears as a service that supports their own native protocols, transports, and on-the-wire formats. Artix quickly performs only those conversions necessary to get callers' messages to the service, without forcing a performance-robbing conversion to a canonical format or protocol in between. Brownfield development doesn't get any more non-invasive than that.
Artix hides these various protocols, transports, and formats behind WSDL. In effect, existing services gain WSDL descriptions without being changed in any way. No need to recompile, relink, requalify, retest, or redeploy. This approach also allows you to consolidate middleware by first wrapping an existing service and then later replacing it with a new implementation built over different middleware. Because of Artix's multi-middleware support and WSDL abstraction capabilities, your callers won't even know you replaced the service implementation.
Of course, building Artix into a new greenfield development is also possible. This allows you to build applications that can painlessly and transparently avail themselves of the numerous protocols, transports, and on-the-wire formats that Artix handles. If such an application needs to speak to a new service reachable only over some other protocol, Artix will dynamically load that new protocol on demand.
If you want to know more, download Artix and try it out for yourself. Artix was designed from day one to tackle the brownfield development inherent in Web Services systems.