Are you looking for packaged photochemicals (XTOL, Rodinal, Ilfosol-S, etc.) or "raw" chemicals (phenidone, sodium sulfite, etc.)? Although there's some overlap, sources for these two categories differ.
For packaged photochemicals, I buy about 50% from
B&H and the remaining 50% from
Dead Link Removed and
Freestyle. The first two are based in New York, which is good for me (in Rhode Island), since I usually get ground shipments in about two days. Freestyle's in California, which would probably work better for you in terms of shipping time, but Freestyle's prices are slightly higher except for their house-brand products.
For raw chemistry,
Photographer's Formulary has, overall, the best selection but the highest prices. B&H will special order most PF items, often at slightly lower prices. Note that PF also sells its own line of pre-mixed chemistry (developers, fixers, etc.).
Art Craft has a somewhat lesser selection overall but better prices.
Digital Truth and
Dead Link Removed (I suspect they're related, but I don't know the details) have somewhat more restricted, but still good, selections and good prices. They're also the only two sources I know of for small quantities of Dimezone S, FWIW.
Dead Link Removed is Canadian and has a good selection and prices, but I've not yet ordered from them myself.
The Chemistry Store has a few photographic items at very good prices, but they mainly cater to home soap and candle makers and so lack a lot of photography items. Finally, an assortment of local stores (supermarkets, drug stores, pool supply stores, etc.) sell certain products that can be used in photochemistry, such as lye, sodium carbonate, vinegar, etc. Note that the non-photochemistry sources might not sell products that are photo grade. Most people report no problems using such products, but there's a risk that you'll get something unsuitable and have problems as a result.
