This article briefly explains how to integrate a HP Procurve and Cisco in one network, and make sure the VLANs are correctly routed across the two switches. I avoid using the term "trunk" as the definition of a "trunk" differs greatly between Cisco and HP: a trunk on a HP Procurve refers in fact to a feature like Cisco's EtherChannel, something entirely different.
Note that for VLAN trunking to work between the two, you need to use the 802.1q protocol. Other protocols, such as Cisco's VTP and ISL do not work on HP Procurve, as they are both Cisco-proprietary.
Multi-port trunking is also outside the scope of this article, but the basics remain the same.