Gary, read AO-5, page 132 of 2002 USPAP.
Standards Rules 2-3 and 8-3 require each appraiser signing a report to state whether or not he or she inspected the subject property and whether anyone not signing the report provided significant professional assistance. This mandatory disclosure informs and protects the client and other users of the appraisal.
Whether you need to be mentioned as having worked on the report depends mostly on what you are doing. If you are providing secretarial assistance, then I believe you do not have to be mentioned. However, if you are providing professional assistance, things like measuring the property, choosing comps, doing the cost approach, making adjustments in the sales approach, etc., then it is a USPAP requirement that this must be spelled out in the appraisal.
I use the following language for my assistant (who does not sign reports yet):
COMMENT ON WORK DONE BY ASSISTANT:
??? provided substantial assistance in the preparation of this report. Specifically, she/he helped inspect the subject, assisted with measuring, drawing and determining size of the subject, filled-out portions of the appraisal form, aided in selection of comps and performed preliminary adjustments to make comps equal to the subject, and assisted with final reconciliation. The appraiser closely supervised the assistant in each step of the appraisal process and further certifies that he/she was not allowed to perform any tasks except for those for which he/she has demonstrated competency.
In Missouri, you cannot count hours worked on appraisals towards meeting your pre-license requirements unless you are so mentioned. In other words, the MREAC does not give appraisal credit for secretarial work.
Now, a word about signing. Different clients are different about this. When I first started signing reports, I signed the left and my mentor signed the right side. However, some clients objected to this, so we changed. I signed the left and my mentor also signed the left (we squished our signatures together within the alloted space). At the time, no one objected to this practice, but I'm not sure it would be the same now. Also, I can't think of any practical way to do this for a report sent by e-mail with a digital signature; maybe someone else who does this will post it here.