Actually, the b18 will be somewhat easier because you won't have to wire for VTEC (i'm assuming you're talking about the LS motor). Just make sure you get an OBD0 motor and it'll be pretty easy. You'll have to rewire your harness for MPFI, but there are a lot of write ups on how to do it all over the net. For both swaps you'll need what Andrew said, plus a shift-linkage (available from hasport). For mounts I highly suggest Hasport, but there are other billet mounts abailable, I think AZ racing makes some that look like exact hasport copies and are probably pretty comperable.
for JDM motors I'd buy from Steve @ Hmotorsonline.com, thats where I got my b16, they're the most reputable dealer in the country.
For a USDM motor just try and find a junked Integra LS in a yard and pull the motor, you can probably get one for $400. The LS tranny sucks so you may want to invest in a b16a SiR tranny b/c of the shorter gearing. You should be able to pick one up for $600.
The b16 and the b18 will be about equally fast, the b18 has more torque but slightly less peak power, but you could always put a b16 head on it later and do an LS-VTEC if you wanted more power.