Don't need to convert to obd2, need to convert to obd1...Which should be simple if you get a harness such as http://www.boomslang.us/obd0.htm

Should be simple with that and a p28 ecu.

I recomend the p28 cuz you wont really have to worry about tuning it. A VAFC (which has to piggy back off a vtec ecu anyway) can be tricky if you don't know what your doing and you'll need dyno time to do it, and if you just do RPM activation, then you wont have any fuel maps for the vtec and it'l run like crap.
One other option is to get the 1-wire conversion from zdyne. It says it's for a b16 but also says it can work for a mini-me swap, which is similar to what your doing of course, you'll have problems with the distributor then though.

Go with the harness, $125, then a p28 $75-100, and maybe s spool of some wire for another $5. Should be all set after that if I'm not missing anything.