A site that's got formulas for C-41 and RA-4 (developers and blixes) is
this one. (The same document appears various other places on the Web.) Its formulas aren't all that close to Kodak's, though. Personally, I use its developers with good results, but I don't use its blixes. (I've tried them but I didn't like the results from the C-41 blix and the RA-4 blix is very weak compared to other formulas I've seen, so I don't trust it.)
(there was a url link here which no longer exists) presents another C-41 formula that purports to get very good results.
This site and
this Usenet post both have other C-41 formulas. The latter includes bleach and fixer formulas. I have yet to try any of these. Note that mix-it-yourself bleaches are either very expensive or are designed around potassium ferricyanide, which Kodak hasn't used for a long time. For bleach, it's much more sensible to buy it commercially if at all possible. (Bleach is the single most expensive step the C-41 process.)
A very strange developer for C-41 is (there was a url link here which no longer exists) which is a divided developer. "On paper," it's got some nice features (use at 75F rather than 100F, long shelf life, low cost), but in my experience it works inconsistently -- some rolls come out well but others don't. I mention it mainly to point this out and suggest you use something else.
For RA-4,
this site has a formula that's supposed to be pretty good; however, it calls for several chemicals that I don't have and that aren't stocked by the usual photochemical suppliers in the US, so I've not tried it.