If you open PSOC designer there is a filterable device catalog link in the
recent projects box that allows you to look at various parts/families.
If you go here another selector guide, and downloadable to Excel - http://www.cypress.com/?id=1573
And this might be of assistance - http://www.cypress.com/?rID=58639
You can download the application note - "AN75320 - Getting Started with PSoC 1" - http://www.cypress.com/?rID=58639. On page 4 of this document there is a table summarizing the feature set based on PSoC 1 families. This could be very handy in selecting a suitable PSoC 1 device for your design.
I have also attached the table for your reference.
Thanks for the info Dana & Anshul. It is much appreciated and this was what I was looking for.