I am assuming you are still working for the WP sponsor and hence your WP visa is still valid. Apply for a spouse visa before your WP visa expires. Visas issued in the UK are now refered to as residence permits.
You can do this on Form
FLR M which will list the documentation required:
1. In person at a Public Enquiry Office e.g. Croydon. Cost is GBP 500 and you may get your visa on the same day if you have all the documentation and no further enquiries are needed. You must make an appointment to attend any PEO. Croydon allowed walk-ins until about two weeks ago.
2. By post at a cost of GBP 335. Home Office service standards say case may take up to 13 weeks for consideration although most of this is due to processing backlogs i.e. your application is in a queue. At present (26 August 2005) their site shows they are processing spouse visas submitted (by post and presumably in person but needing further enquiries) in July 2005.
Initial spouse visa will be granted for 2 years with a restriction/ no recourse to public funds clause. You may work including self employment without needing a WP. 28 days before this visa expires and if your marriage is and will continue to subsist apply for ILR.
If you do not work for the WP sponsor then technically your WP visa is invalid. You need a valid visa for any 'in country' visa/ leave to remain application. The caseworker may exercise discretion and ignore your invalid visa but it is a huge risk to take unless there are serious compelling circumstances that prevent your return home such as a natural disaster. In this case return to your home country and apply for a spouse visa at the
British Diplomatic Post which may require an appointment and/or interview.
Good luck